I know a lot of newer pilots that use after run after every day of flying. Seems dumb, but whatever. There is enough oil in the fuel to take care of it. I have never oiled one after flying. Never had a bad engine. I do use Marvel mystery oil if it is going to sit for a long time. I also use it after cleaning. It works great. I know there are probably better oils in peoples opinions, but I have been doing it this way for as long as I can remember, and it has always worked perfectly. Even used it to unstick an engine that got dumped in the lake by a friend and put away without cleaning for a long time. Didn't think it would ever turn again.