We live in a 1920s building with some seriously thick plaster-over-concrete walls. It definitely beats a new build with cheapie thin materials, but we hear direct neighbors more often than you might expect. Never anything at the level of regular speech or tv, but yelling or loud singing, cranked-up music, barking dogs, instrument practice, and the like all come through the floors and sometimes walls. (Weirdly, we share a wall with a rowhouse next door and don’t get their noise but do get any strong smell leaking through from their house.) And the front door is a weak spot — if people are talking in the hall, we hear every word of that. Not sharing to be a Debbie Downer, just to help you know how much to trust the building construction vs taking other measures like trying to rent on the top floor or to share as few walls as possible. We love our old building for every other reason, especially the original hardwood floors and the fancy trim details that no one uses anymore.