There is wear and tear owing to deferred maintenance. Unlubed and rusty chains stretch and wear the gullets on the sprocket. Eventually the chain rides on top of the sprocket teeth and skips. Shock cords deform and stretch and aren't adjusted or replaced resulting in slow chain return at recovery.
There is wear and tear owing to misuse or abuse. Some folks get a bit rammy and release the handle with chain extended because they find their own performance offensive or they've mistaken erging for inhaling fly spray thru a TP tube and think they're entitled to take the machine down right before they pass out. The result is what ergmeister (another C2 wrench) termed a bowed chain. A laterally bowed chain saws away at the sides of the sprocket teeth. Bowed chains are also the mark of those dear souls who think the erg is a GP cable row machine with a fan instead of a weight stack. Their weird oblique stretching routines shred the black plastic in the chain gate. That is only the tell for the chain deformation that produces the scrubbing/sawing noise that says a relatively new machine is succumbing to premature and unnecessary wear. My favorite is clickedy-clacking over a respectable divot in the stainless rail about 1200 times per medium distance workout. This can happen where heavy objects are used to check that gravity is working properly.
I got no use for apes OR brain-dead yoginis but without them gymworld would be just too perfect and we'd need something else to complain of.
