[oohaargh]

This one's very personal, it's only a good thing to do if you genuinely really enjoy it.

I used to be a maths teacher and I love maths, and would do it for fun outside of my job. That in turn often helped with the job itself, and certainly helped to keep my interest in the subject alive even when 90% of the job was teaching fairly basic stuff that wasn't particularly exciting.

I'm now a software engineer - I'm much happier in my job, but I don't love writing code enough to ever want to be doing it outside the 40 hours a week I'm paid for. I'm slightly jealous of the people who do, because I know first-hand that it's a great way to do better at work and keep feeling fresh and interested in what you do, but forcing yourself to do it doesn't bring any of the same benefits.