The maps on the comparative pages could use a different (ideally equal area) projection. At present, the free-for-all status of Svalbard is extremely prominent :-)
So did I! Although my country, Ireland, isn't explicitly listed.
Looks like it takes "territory" (+40%) as a major input. Russia, China and Mongolia are big countries by land area which have a good understanding with Serbia, but nothing special with EU states. Guessing most Europeans will also hit Serbia. What's the actual most useful second passport to an Irish person? Probably American.
Thanks. I found it there - otherwise, I couldn't have given the details above - but that's the name of the country's soccer team. The country's name is Ireland and that's what appears on my passport and in any official documents produced in any country in the world.
I guess it's similar to Germany being the "Federal Republic of Germany", or China being either the "People's Republic of China" (mainland) or the "Republic of China" (Taiwan).
> I think Japan does not allow for dual citizenship though.
Like Japan, China and the US also do not allow a second citizenship through naturalization. The US oath of allegiance requires you to "renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty". The loophole is that most countries don't allow you to renounce your citizenship just by informing some foreign flunky, so just saying it doesn't make it so. For naturalization, none of China, Japan or the US require documentary evidence that you are no longer a citizen of another state.
"For naturalization, none of China, Japan or the US require documentary evidence that you are no longer a citizen of another state."
That's because international law doesn't allow for states to make citizens stateless. E.g. in The Netherlands, a condition of getting citizenship is that you promise to renounce other citizenships within x time, and your Dutch one will be taken away if you don't. Not saying that any of the countries you listed have similar requirements, I don't know about that, I'm just adding some nationality law pedantry.
Australia is probably the best second passport for EU citizens, since that makes you eligible for E-3 visa to the US as well as the APEC card to China and Russia.
I have to think American citizenship would be a pretty bad choice for a second passport, since America taxes its citizens on income earned abroad. You'd be approximately doubling your taxes if you are already taxed on income while abroad.
America will let you deduct your foreign taxes, so if you live and pay taxes in a high tax country then you in theory won't actually owe anything to the US, but instead you'll owe your accountant for helping you file.
Interesting. I was not aware. Wouldn't you still owe the IRS money if the foreign taxes are deducted?
As far as I understand tax deductions work like: Initial Income - Deduction = Adjusted Income. Then, you owe full taxes on the Adjusted Income.
Let's say European Tax Rate is 40%, American Tax Rate is 20% (hypothetically!)
Foreign income is 100k USD equivalent.
You pay 40k taxes in Europe and are left with 60K.
You deduct 40K from Initial Income, leaving you with adjusted income of 60K. You then pay 20% of that (12K) to the IRS, leaving you with 48K.
So you’re in this hypothetical tax range taxed at less than US+European tax, but still have an effective tax rate much greater than not having US citizenship.
Simple formula I think:
Effective Tax = Income x EuropeanTaxRate + (Income-Income x EuropeanTaxRate) x AmericanTaxRate
You don't pay taxes on on your first like 118k in income [1]. Because this lowers your AGI even if you make more than that you still start at the bottom of the tax bracket. Rough example you make 125k thus 125k-118k - 7k in taxable income thus in 10% bracket. There are obviously other rules for non W-2 income and property taxes.
It's not a deduction, it's a credit so it effectively reduces the amount you pay in taxes to the US by the amount you paid to the foreign country.
Also, you do get an additional separate exemption/deduction (i.e. NOT a credit) up to around the first 100k of foreign earned income, if you meet some rather stringent qualifications.
There are ways to structure things using a foreign corporation to reduce your tax liability. This is changing though with the new 2017 Trump Tax "Cuts" and Jobs Act, which now requires expat business owners to report even their leftover business income as their own personal income (GILTI).
Many expat small business owners stand to be financially devastated because the law even taxes previous business income from the last 30 years in a so-called "transition tax." Ouch.
Don't forget about FATCA, the penalties are incredibly stiff (failure to report yields penalties that are a significant fraction of the amount of money on deposit). Being a US citizen has great benefits, but it comes with large obligations.
Oh yeah, and good luck getting a foreign bank account if you don't already have one. Heck, if you have an American bank account, I've heard European banks don't want to deal with you even if you're a solely European citizen living in Europe.
Right, does this site take into account the obligations, along with the additional freedoms a second citizenship grants? The US' overreaching expat tax laws are a great example, what about the countries that have a mandatory year or two of civil/military service?
American citizenship is probably the next choice, if just for extra State Department freebies.
It's normal for troublesome countries to give more more security to journalists and other American citizens, and the US government rescues idiots stuck North Korea all the time. Most other countries wouldn't lift a finger for their citizens if that would have a significant monetary cost.
It's a total of differently weighted values for all the extra visa free countries, land, population and hdi/freedom of press of the target country. So we're aiming at a country that'd give you access to the most new countries/land/population while being relatively developed and not too totalitarian.
... well, I guess that means I’m a lucky person when it comes to passports. When I reverse search, the best second passport for a German is “Application Error”, and I sure have plenty of those as well :)
Pretty much all countries probably will sell citizenship if you're a multi-billionaire.
The UK situation, for example:
>"Officially called a “Tier 1 investor” visa in the UK, the scheme gives individuals residency in exchange for investing £2m in UK bonds or shares through a bank, with applicants eligible for indefinite leave to remain, and even full citizenship, after five years. That is, unless they can stump up more cash: those offering £5m can settle after three years, and those with £10m after just two." (https://www.theguardian.com/uk-news/2017/jul/04/golden-visa-...)
Now it's the Grauniad so I don't expect it to be completely right but I expect it's close -- [THIS BIT IS WRONG, PROPERTY INVESTMENT IS EXCLUDED: so make a company to buy your small pied-a-terre in London for a few £Million and you get access to citizenship.]
Things have tightened up recently for Russians, not sure about others.
I believe it's for everyone, you basically have to indicate where your money is coming from to a higher degree of detail. It's an anti-money-laundering measure, I think, more than anything. The situation had become shameful, with London being the black-economy capital of the world.
It's down so I can't see, but I assume this is doing a calculation I tried to do using passportindex and had trouble with:
Most passport rankings are by total number of places you can go. But given I already have one passport, what value do I get from a second passport? For example, Canada, USA, Uk, etc have fairly similar sets of countries you can go to. But maybe there's a passport that gets me access to the various middle Eastern and African countries I don't have access to. So maybe something lower overall rated is better as my 2nd passport.
Heroku's standard tier doesn't have auto-scaling. You have to be using the $250/month performance dynos for it. I'd suspect that's not feasible for a little hobby project.
I did not expect it to get any attention, so it was on the free tier dyno when it hit the front page. (And even seem to have held up for some time judging by the logs, before dying from the extreme lack of available ram.) Bumping it to the standard dyno when I noticed the issue was enough to keep it running.
Maybe I'm out of the loop but I feel like the utility would be greatly increased with a sentence or two. I have no idea what the values in the table mean, let alone why I'd want or need a second passport. (Also, what "HDI" is)
I believe Germany makes you renounce your old citizenship in most (not all) cases to gain German citizenship, but you have it listed as allowing it?
Though I believe they recently made an exception for Americans getting charged ridiculous fees to renounce if it was more than a month of income, or similar.
Thanks for making this! I'm a US citizen applying for naturalization in a few months. Here's to 7% more territory! Though really, the EU ought to be something of a block since it means the right to live and work throughout, not just in one country. For now, at least.
Also, worth noting that Republic of Ireland might get a bonus factor, in a sense, for soon being the only passport that lets you work throughout the EU and the UK.
I can confirm this. According to my Netherlands immigration lawyer I can acquire Dutch citizenship because my wife is a Dutch citizen, without needing to renounce my US citizenship.
My guess is that acquisition-by-marriage falls under a different rules category than vanilla naturalization by time and integration and learning the civics and language, which is the pathway an adult would have to take moving to a place where there was no bloodline binding.
To give you some data point with regard to enforcement, my SO has a Japanese passport and acquired US citizenship. No issues entering/leaving Japan after acquiring US citizenship. Japan technically allows only Japanese citizenship past age of 20.
I also have a friend that was born with both US and Japanese. Didn’t have to pick. However, US embassy indicates that even if you notify Japan that you pick Japanese and renounce other citizenships, it is in fact a very formal process (almost difficult) to lose US citizenship.
Yes, even if you are entirely overseas. The US and Eritrea are the only countries in the world that tax all world-wide income. As long as you are a US citizen, you can live anywhere else in the world for however long you want, and you are still taxed in the US and have to file and pay taxes every April.
Not only that, you are required to disclose all of your foreign bank accounts and their balances on a special "FBAR" form to the FinCEN (separate agency from the IRS). Penalties for any "violations" start at $10,000 each (for so-called "non-willful" violations such as using the wrong currency conversion rate or a different bank branch address) and go up to 25% account value for willful violations (everything is conveniently considered "willful" whenever possible to FinCEN in absence of fact, even the aforementioned common mistakes). Many expats get screwed because they simply didn't know about this esoteric form. Hiring a professional to properly prepare your FBAR with their signature on it is necessary as a form of "insurance" (you are welcome to roll the dice and self-prepare), and of course, it is also an expensive proposition.
There is also no clear guidance for what the disclosure requirements are for foreign cryptocurrency exchange accounts or wallets. Anyone living inside or outside the US with a Binance account could get slammed at anytime in the future for not submitting an FBAR.
If before leaving the US, you lived in California, you also have to pay California state taxes on all world-wide income every year, since you are still considered a California "resident."
There is a foreign earned income exemption up to around 100k. This applies to ordinary income only, not capital gains (e.g. cryptocurrency), and you have to meet rather-stringent requirements to qualify. Also, the exempted income still pushes up your capital gains bracket to the highest applicable rate. This exemption does not apply to your California taxes, only your federal taxes.
You almost never hear about how disfavorable the US tax laws are for expats because there are only 8 million of us.
Foreign banks are required to report information about accounts owned by US citizens to the FinCEN (this is called FACTA). You may remember being asked if you are a US citizen when you opened your foreign account -- this is why. If the banks don't provide this information to the US government, then they are heavily sanctioned. Many criticize FACTA for its world policing, and past attempts at repealing it, spearheaded by none other than Rand Paul, have been struck down by the courts.
If something doesn't match up between what the banks reported about you and what you reported, then this triggers an audit. Then, the IRS will request documentation, and if you do not provide it or if it does not match, then you are criminally charged with tax evasion, facing heavy fines and jail time.
This whole sour experience of being an expat and getting screwed in multiple ways has literally turned me into a tax reform lobbyist. It's quite a different experience than importing your W-2 into Turbo Tax in 30 minutes and getting a refund every year like 99% of Americans.
Yes. Even if you've been gone 10 years and never visit and never plan on returning. Some folks find they technically need to pay tax because their parents are American - even though they've never stepped foot on American soil.
There are exceptions for local taxes, but you still have to file tax returns.
It’s quite irregular. As an American abroad, we get zero awareness or sympathy from people „back home“. They either assume it is normal among countries or that it doesn’t exist.
Taxation treaties only go so far. Declaration overhead, schedule category, and tests make the process hellish. And I haven’t even begun to mention the FBAR and other disclosures. It hurts everyday Americans abroad and barely differentiates against real versus nominal income and cost level.
There are loopholes. I am a us-german-uk-other citizen, due to birth in Germany and naturalisation in the us and another country as a child. Acquiring new citizenships as an adult is difficult, but also possible if i obtain a waiver.
You can obtain the German citizenship without renouncing to the Chilean. From what I remember, you can't acquire a third (need to renounce to one). This is also true for other EU passports.
Born in Denmark to a Danish father and American mother. When you're born on foreign soil to an American parent that parent declares your birth to the United States and you receive a Consular Report of Birth Abroad: your US birth certificate.
I know for a fact the Danish state allows for dual-nationals because I just renewed my Danish passport and because of new biometrics requires dual-nationals to give a copy of this Report.
There's one big downside to all this, since Denmark now knows very clearly I am two people. Should the state decide to revoke this law I will most likely be forced to choose. Which would be unfortunate, since I can't imagine living in just one or the other country.
This is a cool site! One minor bug, the “third passport” link in the “see also” section seems to be mistranslated. It says “nacionales” instead of “nationals”.
One thing that may have been good to add, is the length of time / financial requirements to get citizenship.
For example, I'm personally planning to move to Ireland relatively soon; in part because it's one of the easiest to get dual citizenship (5 of the last 9 years)[1].
Same, though not solely for EU citizenship, but also because I love Ireland. My issue is just getting a job, so it's likely going to be back to school for me, which will push off the counter for years, but give me more networking opportunities.
The thing that's difficult in Ireland is internet access if you're living outside of Dublin. We looked at moving to Dingle for a bit, but we couldn't find anything available (from America) that had high speed internet. Granted, it was out in the countryside, so I completely understand, but it was a non-starter as far as going there for a remote job was. It's just something you have to keep in mind that if you're coming from an American city you may not think about.
I know several people that are dual citizens of China and US. China doesn't recognise the second citizenship, but that doesn't prevent you having it. If China finds out, though, they'll apparently strip you of your Chinese citizenship.
Travel between US/CN will be a hassle for those people because the border control officials of China won't let you board the flight if you show your CN passport doesn't have US visa. One loophole is that you can use Hong Kong as the middle hop since you don't need passport to visit HK.
The dual citizen status is actually very common. If a child's parents are Chinese citizen working/studying in US with a temporary visa (H1b, F1) and the child was born in US, the child is eligible to be a Chinese citizen, thus a dual citizenship.
Is there something like this that takes into account long term stays?
I.e. if I'm a US Citizen, it would probably be more advantageous to have an EU Nation 2nd Passport so I have unrestricted access to all EU member countries
For what two countries are you a dual citizen? Which one isn't worth the effort to keep up to date?
I'm a dual citizen for the United States and Mexico, and it's fairly easy to update my Mexican passport here in the United States - not sure if that's the case inversely.
I live in vancouver so my choices include a 4.5 hrs flight to Toronto, paying very close attention when they travel to Vancouver (which is effin rare, see https://ottawa.mfa.gov.hu/eng/page/kihelyezett-uegyfelfogada... -- right now if you try to get an appointment you simply get a 'no appointments available' error) or just renew my passport in Hungary. For me, that's relatively easy since I am back there at least twice a year so that's OK. But the bastards just changed the procedures so the valid date is your last birthday so when I recently renewed I got 9 years and 1.5 months instead of ten years. And, if all goes by plan in a few years I won't travel to Hungary ever again so this will become a major hassle but as long as the idiot government doesn't pull a Huxit it's still worth it because it gives me free movement in the EU.
For my European country, you can renew at the consulate in San Francisco 1-2 times a year, but the slots sell out as fast as Burning Man. The passport costs ~$200, and I think it's only valid for 5 years, not 10, when you're not a resident.
I have been hit with $150-200 visa fees 2-3 times with my US passport that my European one would have avoided, but in hindsight it was a good deal.
Hmmm. I have dual citizenship for Australia and Estonia, both of which offer 10-year passports. It's also possible to moderately easily get the 'other' passport when located in each country. Thinking about it I guess I could be pretty fortunate, and this might not be the case with other combinations.
Yeah, it's a bit of a bother logistically because of where the embassy is located, and one cannot be sure you get processed that day if the queues are long. So I keep just one of the passports as paper version (the country where I reside) and use that when travelling. For the other one, I have no paper passport; I do have the social security number which I can use when necessary.
Mind you these are two Nordic countries so it is not much of a difference either way.
Even for voting, which the tool misses, is conviently done. I vote in country B elections from country A. They have lists of country B social security number with a name for the eligible votets, I have the paper which they mailed to me from B and present that while I prove myself using passport/driver's license of country A. Then I vote remotely, in advance to the actual voting day.
Voting in EU elections works the same way, but is done for one country only.
Comparing Australia and Canada shows they have the same ease of access to US. This is not correct, since Australians have to apply online for an ESTA prior to travel.
Could you please add options for 3 passports? I actually have US/Canada/Finland and it would be interesting to see, although US v Canada is probably almost identical.
145 comments
[ 17.1 ms ] story [ 569 ms ] threadI.e. I get told that the best second nationality I could get is Serbian... Why though?
Looks like it takes "territory" (+40%) as a major input. Russia, China and Mongolia are big countries by land area which have a good understanding with Serbia, but nothing special with EU states. Guessing most Europeans will also hit Serbia. What's the actual most useful second passport to an Irish person? Probably American.
I guess it's similar to Germany being the "Federal Republic of Germany", or China being either the "People's Republic of China" (mainland) or the "Republic of China" (Taiwan).
It's listed as the Republic of Ireland, afaict.
As you already have the EU covered, US, China or Japan would be good ones. I think Japan does not allow for dual citizenship though.
> I think Japan does not allow for dual citizenship though.
Like Japan, China and the US also do not allow a second citizenship through naturalization. The US oath of allegiance requires you to "renounce and abjure all allegiance and fidelity to any foreign prince, potentate, state, or sovereignty". The loophole is that most countries don't allow you to renounce your citizenship just by informing some foreign flunky, so just saying it doesn't make it so. For naturalization, none of China, Japan or the US require documentary evidence that you are no longer a citizen of another state.
That's because international law doesn't allow for states to make citizens stateless. E.g. in The Netherlands, a condition of getting citizenship is that you promise to renounce other citizenships within x time, and your Dutch one will be taken away if you don't. Not saying that any of the countries you listed have similar requirements, I don't know about that, I'm just adding some nationality law pedantry.
(FWIW I'm an American)
As far as I understand tax deductions work like: Initial Income - Deduction = Adjusted Income. Then, you owe full taxes on the Adjusted Income.
Let's say European Tax Rate is 40%, American Tax Rate is 20% (hypothetically!)
Foreign income is 100k USD equivalent.
You pay 40k taxes in Europe and are left with 60K.
You deduct 40K from Initial Income, leaving you with adjusted income of 60K. You then pay 20% of that (12K) to the IRS, leaving you with 48K.
So you’re in this hypothetical tax range taxed at less than US+European tax, but still have an effective tax rate much greater than not having US citizenship.
Simple formula I think:
Effective Tax = Income x EuropeanTaxRate + (Income-Income x EuropeanTaxRate) x AmericanTaxRate
Factor out income etc. I’m on my phone :-)
[1] https://en.wikipedia.org/wiki/Foreign_earned_income_exclusio...
Also, you do get an additional separate exemption/deduction (i.e. NOT a credit) up to around the first 100k of foreign earned income, if you meet some rather stringent qualifications.
There are ways to structure things using a foreign corporation to reduce your tax liability. This is changing though with the new 2017 Trump Tax "Cuts" and Jobs Act, which now requires expat business owners to report even their leftover business income as their own personal income (GILTI).
Many expat small business owners stand to be financially devastated because the law even taxes previous business income from the last 30 years in a so-called "transition tax." Ouch.
It's normal for troublesome countries to give more more security to journalists and other American citizens, and the US government rescues idiots stuck North Korea all the time. Most other countries wouldn't lift a finger for their citizens if that would have a significant monetary cost.
That’s due to agreements between non-aligned counties signed by Jugoslavia that Serbia inherited.
You cannot still enter those countries without a visa with an EU passport, thus making a Serbian passport quite advantageous if you are a EU citizen.
I should have said that Jugoslavia had different friends that most other European countries, and Serbia inherited some of those agreements.
... well, I guess that means I’m a lucky person when it comes to passports. When I reverse search, the best second passport for a German is “Application Error”, and I sure have plenty of those as well :)
The UK situation, for example:
>"Officially called a “Tier 1 investor” visa in the UK, the scheme gives individuals residency in exchange for investing £2m in UK bonds or shares through a bank, with applicants eligible for indefinite leave to remain, and even full citizenship, after five years. That is, unless they can stump up more cash: those offering £5m can settle after three years, and those with £10m after just two." (https://www.theguardian.com/uk-news/2017/jul/04/golden-visa-...)
Now it's the Grauniad so I don't expect it to be completely right but I expect it's close -- [THIS BIT IS WRONG, PROPERTY INVESTMENT IS EXCLUDED: so make a company to buy your small pied-a-terre in London for a few £Million and you get access to citizenship.]
Things have tightened up recently for Russians, not sure about others.
See also https://www.gov.uk/tier-1-investor.
I just don't see it being that accessible in Africa.
I believe it's for everyone, you basically have to indicate where your money is coming from to a higher degree of detail. It's an anti-money-laundering measure, I think, more than anything. The situation had become shameful, with London being the black-economy capital of the world.
Most passport rankings are by total number of places you can go. But given I already have one passport, what value do I get from a second passport? For example, Canada, USA, Uk, etc have fairly similar sets of countries you can go to. But maybe there's a passport that gets me access to the various middle Eastern and African countries I don't have access to. So maybe something lower overall rated is better as my 2nd passport.
It'll show you what you get out of a second, third etc passport.
Though I believe they recently made an exception for Americans getting charged ridiculous fees to renounce if it was more than a month of income, or similar.
Thanks for making this! I'm a US citizen applying for naturalization in a few months. Here's to 7% more territory! Though really, the EU ought to be something of a block since it means the right to live and work throughout, not just in one country. For now, at least.
Also, worth noting that Republic of Ireland might get a bonus factor, in a sense, for soon being the only passport that lets you work throughout the EU and the UK.
Same for The Netherlands[1]
[1] https://www.government.nl/topics/dutch-nationality/dual-nati...
I also have a friend that was born with both US and Japanese. Didn’t have to pick. However, US embassy indicates that even if you notify Japan that you pick Japanese and renounce other citizenships, it is in fact a very formal process (almost difficult) to lose US citizenship.
Not only that, you are required to disclose all of your foreign bank accounts and their balances on a special "FBAR" form to the FinCEN (separate agency from the IRS). Penalties for any "violations" start at $10,000 each (for so-called "non-willful" violations such as using the wrong currency conversion rate or a different bank branch address) and go up to 25% account value for willful violations (everything is conveniently considered "willful" whenever possible to FinCEN in absence of fact, even the aforementioned common mistakes). Many expats get screwed because they simply didn't know about this esoteric form. Hiring a professional to properly prepare your FBAR with their signature on it is necessary as a form of "insurance" (you are welcome to roll the dice and self-prepare), and of course, it is also an expensive proposition.
There is also no clear guidance for what the disclosure requirements are for foreign cryptocurrency exchange accounts or wallets. Anyone living inside or outside the US with a Binance account could get slammed at anytime in the future for not submitting an FBAR.
If before leaving the US, you lived in California, you also have to pay California state taxes on all world-wide income every year, since you are still considered a California "resident."
There is a foreign earned income exemption up to around 100k. This applies to ordinary income only, not capital gains (e.g. cryptocurrency), and you have to meet rather-stringent requirements to qualify. Also, the exempted income still pushes up your capital gains bracket to the highest applicable rate. This exemption does not apply to your California taxes, only your federal taxes.
You almost never hear about how disfavorable the US tax laws are for expats because there are only 8 million of us.
No taxation without representation, right?
https://www.economist.com/democracy-in-america/2016/11/02/am...
Foreign banks are required to report information about accounts owned by US citizens to the FinCEN (this is called FACTA). You may remember being asked if you are a US citizen when you opened your foreign account -- this is why. If the banks don't provide this information to the US government, then they are heavily sanctioned. Many criticize FACTA for its world policing, and past attempts at repealing it, spearheaded by none other than Rand Paul, have been struck down by the courts.
If something doesn't match up between what the banks reported about you and what you reported, then this triggers an audit. Then, the IRS will request documentation, and if you do not provide it or if it does not match, then you are criminally charged with tax evasion, facing heavy fines and jail time.
This whole sour experience of being an expat and getting screwed in multiple ways has literally turned me into a tax reform lobbyist. It's quite a different experience than importing your W-2 into Turbo Tax in 30 minutes and getting a refund every year like 99% of Americans.
There are exceptions for local taxes, but you still have to file tax returns.
It’s quite irregular. As an American abroad, we get zero awareness or sympathy from people „back home“. They either assume it is normal among countries or that it doesn’t exist.
Taxation treaties only go so far. Declaration overhead, schedule category, and tests make the process hellish. And I haven’t even begun to mention the FBAR and other disclosures. It hurts everyday Americans abroad and barely differentiates against real versus nominal income and cost level.
[1] https://www.thelocal.dk/20141218/denmark-passes-dual-citizen...
I know for a fact the Danish state allows for dual-nationals because I just renewed my Danish passport and because of new biometrics requires dual-nationals to give a copy of this Report.
There's one big downside to all this, since Denmark now knows very clearly I am two people. Should the state decide to revoke this law I will most likely be forced to choose. Which would be unfortunate, since I can't imagine living in just one or the other country.
For example, I'm personally planning to move to Ireland relatively soon; in part because it's one of the easiest to get dual citizenship (5 of the last 9 years)[1].
[1] https://www.quora.com/Which-EU-country-has-the-easiest-citiz...
Lots of houses have been connected in the last 2-3 years.
https://passports.io
Says nothing about taxes, capital gain, property ownership rights or how long it takes to become a PR.
The dual citizen status is actually very common. If a child's parents are Chinese citizen working/studying in US with a temporary visa (H1b, F1) and the child was born in US, the child is eligible to be a Chinese citizen, thus a dual citizenship.
I.e. if I'm a US Citizen, it would probably be more advantageous to have an EU Nation 2nd Passport so I have unrestricted access to all EU member countries
Keeping two passports up to date is a non trivial amount of work and expenses, and perhaps travel. Depending on the two countries, of course.
Unless you travel a fair amount, it is often not worth the effort. I've given up on keeping my old passport current, and feel good!
I'm a dual citizen for the United States and Mexico, and it's fairly easy to update my Mexican passport here in the United States - not sure if that's the case inversely.
I live in vancouver so my choices include a 4.5 hrs flight to Toronto, paying very close attention when they travel to Vancouver (which is effin rare, see https://ottawa.mfa.gov.hu/eng/page/kihelyezett-uegyfelfogada... -- right now if you try to get an appointment you simply get a 'no appointments available' error) or just renew my passport in Hungary. For me, that's relatively easy since I am back there at least twice a year so that's OK. But the bastards just changed the procedures so the valid date is your last birthday so when I recently renewed I got 9 years and 1.5 months instead of ten years. And, if all goes by plan in a few years I won't travel to Hungary ever again so this will become a major hassle but as long as the idiot government doesn't pull a Huxit it's still worth it because it gives me free movement in the EU.
I have been hit with $150-200 visa fees 2-3 times with my US passport that my European one would have avoided, but in hindsight it was a good deal.
Mind you these are two Nordic countries so it is not much of a difference either way.
Even for voting, which the tool misses, is conviently done. I vote in country B elections from country A. They have lists of country B social security number with a name for the eligible votets, I have the paper which they mailed to me from B and present that while I prove myself using passport/driver's license of country A. Then I vote remotely, in advance to the actual voting day.
Voting in EU elections works the same way, but is done for one country only.
how about Estonia
(The only place in the world where the internet is protected in the constitution... !)
https://en.m.wikipedia.org/wiki/Estonian_nationality_law