Anyone FIRE and pursue higher education?

Hi FIRE!

Has anyone FIRE’d and pursued a PhD program? How did that go?

I’m currently 36 and looking to potentially aiming to lean FIRE in the next ~5 years, but it’s more so to move from a high paying tech job into a more mentally or physically stimulating, that can still pay basic bills so that I can let my investments continue growing.

I love learning and getting a PhD seems like a lot of fun, especially if I’m not going to have the stresses of having no money as a student that many other students go through.

My main concerns are 1) going back for a PhD as an older person, and 2) if I should do something else