As a middle point, I’ve been living at my house in the Midwest for 4 years now and while we have locks, I didn’t changed them out from the previous owners. I suppose they could have some extra keys but I trust that they don’t and won’t come into my house (and unless they’re playing a really long game, they haven’t, and the previous owners live fairly close as we got some letters from their child’s daycare accidentally sent to us).