One issue I had with my 42T ring was that the teeth didn't wear evenly. So, I think there was much greater wear at the spot perpendicular from the pedals than straight in line with the pedals, due to lots of standing hill climbs, and uneven forces through the stroke. When I replaced the chain, I got a lot of annoying chain noise. I ended up replacing the ring with a 41T ring.

Since then, I've started occasionally rotating my rings (depending on whether a crank guard pin is used on the outer ring, or just rotating the inner ring.

Like with a cassette, a stretched chain can fit in a larger circle, and the chain may try to ride high on the teeth which can be damaging to the teeth and the ring in general.