If there are deep gouges or grooves in them... If you can catch your fingernail on it when running it across the bearing "defect", you should consider replacing it...
It also depends on the bearing material... Babbitt is more forgiving that aluminum...
When we installed the bearings at the engine factory, we not only had to measure and meet a size spec, but also had to meet a surface finish spec... You need a special machine with a stylus to measure surface finish that is not affordable to us home builders...
