I once had an aquaintance in Manhattan. I don’t know how many rooms were in his apartment, because I never saw more than 3 feet in front of me. Picture this: a room that is solidly filled with stacks of refuse, wall to wall, floor to ceiling, with a 2-foot wide “canyon” allowing you to get through to the next room. If there were no next room, the refuse would literally fill the entire 3D space. Stacks of old newspapers and magazines, stacks of crates of cans and bottles, all from floor to ceiling, wall to wall, obliterating windows and unused doorways. One question I cannot answer is why his floors didn’t collapse into the apartment below.
My house tends to get cluttered, because I have so many interests and hobbies in addition to my work. The main problem is finding a proper place for everything and keeping it there. I do eventually get around to putting things away, one small area at a time. And yes, I do suffer from chronic depression with mild OCD, though I’m reluctant to use that as an excuse. (And don’t make the mistake of thinking that only the Felix Ungers of the world have OCD; the Oscar Madisons have it too.)
My partner is the opposite. Few of his interests or hobbies take up much space, and he can’t understand why I don’t always tidy up after a given activity. When we were living together it was a constant strain for both of us (he kept putting my stuff away, and I couldn’t fine anything). Our solution is to live next door to each other.