Want to keep things simple? Stay single.
Nothing will increase your worldly possessions load like a wifette. Even a female roommate will leave no flat surfaces uncluttered. Not that I'm setting out to be sexist here, it just that women like to line the nest with things, cover the walls with things, cover the tables, desks, countertops, dressers, night-stands, bathroom/pantry/cupboard shelves with "stuff". I think it's part of the early reptillian brain behavior humans have which is geared towards securing a mate, marking territory, and asserting dominance. :-)
I also like simplicity, so while I'm being such a misogynistic bugger, I often wish I'd taken my own advice.
Cheers.