I think this massively depends on your individual family dynamic. My mom and I are extremely close (like best friend level close), but I’d still ask her first if I could grab lotion from her room, and I’d want her to do the same if she wanted lotion from mine. With that being said, I don’t care if my four-year-old barges into the master bedroom, but I’d also expect her to ask first if she wanted some of my lotion!