The examples typically cited are well-worn bicycles, the steering wheel on a vintage car, a leather wallet, etc. Seems related to patina but not the same. This may be a neologism.
E.g. "The ______ of the steering wheel speaks to the years of use and loving care John put into his Roadster."
Interesting, here they call it "aesthetics of use" but I'm certain there is a single term.