My Magnum .91fs has at least 100 run hours on it, possibly 150. I'm thinking of changing my bearings. While I'm at it, a new ring too. It runs great and has good compression and conventional thinking is "if it ain't broke, don't fix it".

Do you guys change your rings and bearings on a routine engine hour accumulation or just wait until it's showing signs of wear? I would rather go ahead and change bearings before an issue arises......