1. Yes, most people will tell you not to host your own email, because its too complicated/difficult to get your mail delivered reliably.

A lot of this is FUD. Yes, email is a bit more difficult to get right than say, hosting a web app behind Nginx. It's an old protocol, with many "features" bolted on years later to combat spam.

I'm not sure how email is easier to "hack," unless there is a zero day in Postfix or something. Back in the day, lots of script kiddies would find poorly configured mail servers that were happy to act as an open relay...maybe the stigma persists?

To deliver mail reliably, you need 4 things (in my experience):

- A static, public IP address with a good reputation (ie, not on any spam blacklists)

- A reverse DNS record that resolves back to your mail server's IP

- A domain SPF record that says that your mail server is allowed to deliver mail

- DKIM records and proper signing of outgoing messages (DMARC records help too)

2. I have a residential cable internet connection, but pay extra for static IPs. You can probably get by with a dynamic IP and some kind of dynamic DNS service, as long as you don't want to send email. You could still receive email locally if your MX recorded pointed to some kind of dynamic DNS record.

Note that some ISPs explicitly block outbound traffic on port 25 due to spammers. You might need to check with yours.

3. The only things I expose to the internet are Postfix (to send/receive emails), XMPP (to chat with others), and my web server. Everything else (calendar/contacts, IMAP, Syncthing, etc) stays behind my firewall, accessible only to internal hosts. I use wireguard on my Android phone to access these services seamlessly when I leave the house.

I've never bothered to conceal my IP address. For awhile, I experimented with using Mullvad VPN for all my egress traffic. Unfortunately I spent all day solving CAPTCHAs...wasn't worth it (for me, anyway).

EDIT: I should add, that I also have a "normie" email address at one of the usual providers that I use for really important things like bank accounts / utility providers. If I get hit by a bus, I don't want my (very nontechnical) wife to deal with sysadminning on top of my early death.

For all our personal communications though, we use my selfhosted email domain.