depends on how much your plane weighs some are rather heavy, now granted this is the beginner forum some of my planes are only 5lbs total some allot more I was also referring to the airframe also mount,fire wall, berings do accumulate stress in high load situations over time metal subject to constant load then applied pressure wear faster over time 12,000 rpm is a load of pressure.
it is about what works for you and your space I know what works for me and what I have been told by more expierenced modelers just passing on the info and what I do to keep the engines I have in working order like oilling after use especially 4 strokes as they have the most moving parts.