I think many components could show wear. Perhaps less for some mechanics than others, but for example, I've rounded a few spoke nipples in my life. Ok, so a 10 cent piece, just remove it and reinstall.

Occasionally one will gall threads. Probably less so if one is careful to lube them?

I hate those old Regida 2 prong freewheels. Even with the greatest care, eventually they'll get the slots rounded, especially if one gets it mashed on good and tight.

I would think there would be issues with some tools, so as both parts and tools wear,the tools may eventually get to a point where they will no longer hold the worn parts.