Grew up in an open house, no one was expected to knock, on,y front door was locked so folks came in the side door. My parents used to stop by my house numerous times a day, never knocked, I never knew when they were coming. Our doors are open, kids friends know to just walk in, as do mine. When going to friends’ houses for planned events everyone walks in (maybe say knock knock). Our driveway is behind the house, so usually just immediate family walks in that door because they just parked in the driveway. With 5 kids, folks were always coming or going. My youngest is 22 and still has friends sleep over a few times a week. Dd24’s boyfriend lives here too, for his job.