ORIGINAL: NM2K
I wait until they show signs of wear before changing out any major components. I can't see wasting the money. Besides, model engines generally aren't worth rebuilding anyway.
Ed Cregger
I can see where some engines wouldn't be viable to rebuild but here it's different, IMHO.
New Magnum .91fs - $190, $140 if caught on sale.
New ring and bearings - $25 total. If that's all it needs then to me it's definately worth it but I do agree that everyone is different though.