> I've had equity in most of my jobs and the job sucks then I'll leave before my stock vests which I've done twice.

Sometimes you can't tell how it will be from the outside. You only know whether you'll like the job, or whether it has prospects, after trying it.

Bouncing isn't a bad move. In fact it's smart from a diversification perspective. Once you realize a company has no future, just get out and try again. As an employee, choosing whom to work for is one of the few ways you can diversify against risk.