I think there's a difference between working for free and doing occasional favors if you have the time and it's a two way street (no need to keep score, just in general).

Work often implies responsibilities and demands. There can be none in a favor.

> it makes sense to do those things for them.

I try to "teach them to fish", not just "give them the fish", though. Unless it's too complex or we're too pressed for time.