answer:I walk right in. Most of my adult life I have lived out of state, but when I am in town I would never knock, I would have a key. My parents when they are visiting me also have a key and treat the house as their home. Same with visiting my inlaws we just walk in. However, if I lived nearby I would probably knock, not sure? It would probably depend on whether my parents were expecting me or not. When we lived near my inlaws we would knock first, because we did not have their key, so we had to basically. But, when we stay with them now, we are given a key and we never knock when entering their home. I say just ask them to knock first. Or, keep your doors locked. My door is always locked.