I work 40 hours a week as a consultant, but I do read/write blogs, prepare for sessions, answer forum questions et cetera in the evening (1 to 2 hours on average). As others have said, this isn't really "part of the job", it's part of my career and it is a hobby as well. But I do it (most of the time) with pleasure. Once it starts feeling like a drag, it's time to wind down. I usually play some games then or watch some tv series. Until my batteries are charged again.

Weekends are off-limits though. 100% family time. I even try not to read e-mail then 🙂

This means I'll never get to do a SQLSaturDay, but hey, I'll live 🙂