While Mike Kone's advice might be very cautious, way back in the day, the Campagnolo cranks that broke and came to the bike shop all showed "polishing" of the arms by either a toe strap or an ankle / heel. When we had the chance we addressed this by looking a cleat placement, pedal type and made suggestions, Pista pedals instead of Strada often helped, often customized in the shop area, adjusting the toe clip location too.
One rider had worn away 2+mm of material away from the arm from the ball of his foot. We got him on new arms before there was a asphalt moment.
There were other breakages, such as from a fellow who just HAD to grease the taper on the crank spindle and over-torqued, it failed on the stand.
There are ways to check for cracks, "crack check" dyes can help.
To the shop a rider who had to re-torque his cranks periodically was reason to see why, often there was a problem, mismatch of spindle type or grease again.
While this is possibly overblown, and someone doing their own work to their own parts is probably not a problem. Buying refurbished parts where one does not know what they looked like before polishing, is something I would shy away from for a rider bike, but not polished parts as a type.
John Jorgensen
Torrance Ca USA