Evening Destructor,really I have no idea how long an engine last. I read in one of the r/c magazine's that the ave. r/c engine lasted 15 hours of running. I break an engine in by the instructions,run 300 to 500 rpm on the rich side,use fuel with a blend of oil,castor/syn.install filter on carb,change when dirty,after each day of flying I disconn the fuel line from the carb.then burn the fuel out of the engine.Then I'll put 15 to 20 drops of air tool oil in the engine,if 2s in the carb,if 4s in the vent tube,if I'm not going to fly a engine for a while then I pull the glow plug,flush the engine with paint thinner or acetone,then install air tool oil the same plus a half dozen or more drops in the glow plug hole. Then hang the plane level until I,m ready to fly that plane again.