Ask HN: Should I join a startup? How do I tell if I'm ready?

Should I join a startup?

- I'm thirty yrs old and single. - Currently working at a major internet company in Bay Area. - My pretax income is ~$300K/yr. In next 1-2 yrs, it might reach 300k~350k/yr. Now debt-free and I rent an apartment. - I have experience with various projects and I can consider myself as a fullstack engineer. I do have a few side projects including some mobile apps on appstore and webapps running on aws.

Motivations for me, * I like the feeling of building things, making them usable by others and making improvements. * I like to get big financial rewards by joining a startup (eventually). In the past few years, I have friends got rich by joining pre-IPO companies, like fb/twtr and made millions. And most recently Uber/Airbnb/Pinterest/Snapchat/Zenefits become more popular as they might go IPO later. * (Those names are hot but I've also seen people didn't get big financial reward in buzzword companies like evernote and square, even zynga and groupon.)

Should I join a startup? What are the things you consider before you join a startup leaving a nice salary? When do you know you are ready?