I had changed careers and gotten out of computers (IT and dev) at about that age. I should have stayed kept out of computers instead of coming back to them.
Audio recording and production. I had been a musician for a couple decades at that point and did some schooling and got my AES engineering certification, but didn't move to a city where audio jobs would exist (in more plentitude than here) and pay well. In hindsight, I realize that I could have managed the move with only moderate risk and likely could have gotten a great reference from a well-known engineer. Instead, I sat at home, in the dark, smoking and drinking and sliding back into coding.