I never rang doorbells. I would always knock. There was a better chance they might not hear the knock, as it wasn't ringing loudly throughout the house. I usually didn't do too much deliberate "light knocking", I just chose knocking over doorbells.
I would have people sometimes say "there's s doorbell, you can just ring it". I wanted to tell them that when it's their door, they can do whatever they like, but don't worry about my doors". LOL
-mentallyfree31-