Doing the legwork to get back to school and lining your life up with the admissions schedule can take a year or more of planning before it's safe to quit your day job. It helps if other people you know are doing the same thing at the same time. But one thing it doesn't require is getting rich beforehand.

Good question. That made me think a bit. Because I'm not unsatisfied with what I'm doing now and because I'm not confident that I would be effective in that field, at least not for a long time. I took the original question as more of if you weren't doing what you were doing now and you could do anything in the world, what would it be? Also, I agree with etal's comment about the legwork and planning. It takes a lot of effort and frictional costs to get out of one situation and into another. I don't know. It's something to think about.