It's a personal decision that's hard to come up with hard and fast rules for. I know for me, every time I've found myself suddenly without income, I've been able to bounce back faster than if I'd been in the position of having to juggle a job hunt with my job.
I would probably be much more willing to leave a startup at the drop of a hat over a safer and more stable corporate job like the one I'm at now. A corporate job has a history and a set culture that's predictable and not quite as subject to the whims and emotions of those at the top. A startup can get real hellish real quickly.
I quit my job last week, with nothing in particular to go to (luckily I have a little runaway).
I guess time will tell if it was the right decision, but it is a personal one. Startups can be a nightmare, burn you out and cause serious personal issues. Sometimes staying just to have a job is not the right decision.
It doesn't make sense for anyone to give forceful advice on this I guess.
I would probably be much more willing to leave a startup at the drop of a hat over a safer and more stable corporate job like the one I'm at now. A corporate job has a history and a set culture that's predictable and not quite as subject to the whims and emotions of those at the top. A startup can get real hellish real quickly.