I've always liked the philosophy that some chores you get paid to do, AFTER other chores you're expected to do as a productive member of the family.

Then bonus opportunities exist. Something out of the ordinary, or something you do that's someone else's job.

Entrepreneurial kids with siblings can rake it in.

Parent(s) get more flexibility to start a lower base.

I also like to give my kids small, unexpected money when they show good character, or work at a positive habit I'm trying to instill.