is it a good idea to fix your kids' cars for them?

On my daughters car I fixed everything and kept it perfect. She paid for the parts and I would run it though the shop and I paid my Guys. My sons (who work for me now) were given advice, keys to the shop all the info they needed but it was up to them to fix it. I would teach how to do things and then they were expected to do it. My 23 year old is on of the best techs in the area and he can think while working on stuff. It is the teach a man to fish thing.