I'm well aware that I should take internet forum advice with a grain of salt. But, I thoght that sparking a discussion about the complexities and circumstances in an internet forum that has a very wide, deep pool of experience in this area might shed light on some interesting things. So far, it has.
Here's another one: When should/shouldn't you exercise options when leaving a startup?
Obviously, if you're leaving Uber you'd be wise to buy your vested equity if you can.
Obviously, if you're leaving a company that is crumbling, you probably shouldn't.
But what about an earlier, Series A/B startup that's promising but still shows a lot of risk? Or what about a later stage startup that is doing well but not on a guaranteed path to a huge exit? On what information would you decide whether or not to exercise?
Also, please add more questions if you have them. I'm sure I didn't ask all the pertinent ones, and if there's any place to find people who can answer, it's probably HN.