Strict Hygiene Rules
Be it a roommate, family member, child, or friend, stress on how much cleaner and spacious a room looks when things are put in their rightful places. Don't give anyone a chance to sift through your stuff and remove old items that need to go (if they're in good condition, you may ask them to see if they'd like to keep something). But, be sure they don't take what they want and not use them.