You may use your finger to rotate the engine bearings. The bearings must be smooth like new. It is good that u rotate an entirely new bearing for comparision.
For some engines, this method is useless as some bearings will suddenly fail even though they seem to be very smooth. Then u better record the amount of fuel used by the engine. When certain amount of fuel has been consumed by the engine, you just change the engine bearings, conrod, pin and clips no matter what.