I've worn my childhood engines out more than once each. Dished treads, worn slots in shoes and cut rollers in half on Super O. Wore the thin center rails out on that too. I think I once ran the Adriatic non-stop for three days before Ma caught on ;D I need it's 4th bushings and second gear set for it right now
I bet I do half the wear dressing the brushes flat when I clean .