My parents are both deceased, but when they were alive I wouldn’t dream of visiting without first calling. That was my personal way of doing things, not theirs. Once there, I wouldn’t knock because that’s not how they wanted things. In warm weather the doors would all be open.
My kids do not live nearby now, but they know I’m not cool with surprise visits. If someone were to knock at our door right now, I probably wouldn’t answer. My gf is in the barn cleaning horse stalls, so if she saw a car drive up she might go see who it is, but anyone I want to socialize with knows better than to not text first.
I never knocked when I went to the house I grew up in. When my parents moved out of that house, it no longer felt normal to just go around to the back door and let myself in like I did when I was a teenager. Then my parents got a slew of small, yappy dogs, and it became very obvious very quickly that knocking was less polite and more of a pain, and I stopped. My parents are once again moving into another, smaller house, and no longer have the yappy dogs, but I’m not sure whether I’ll go back to knocking. They don’t seem to expect it, and I generally am attempting to cart in their rambunctious grandchild and her assorted paraphernalia, which makes knocking and waiting awkward.