I have been fixing motors on the side for a little while now. Bearings go more often than you might think. Sometimes its just poor seating of the bearing, high heat, lack of lubrication etc. As long as the bearing journals are fine replacing the bearings in an induction motor can be worth it for just a few bucks.
I have restored some older 3 phase motors by replacing the bearings, cleaning and checking the windings, making sure no shorts.. Actually have made a few bucks selling them.