I don't think waiting until it slows is ANY indicator. By that time it's probably too late. I have seen them run real good before they come apart as well. Experience will give us a maintenance plan that will work. My rotating assembly is more than 15 years old and has more than 1000 passes. Even though it probably checks out, I will replace it before I race it very much more. I have replaced roller lifters, intermediate shaft gears and valve springs. Normal stuff for longevity in a very happy combo. It has only been totally freshened once in 2012. Honed the cyls. and installed a slightly larger ring pack. Bearings are coated and were re-used.