I once had a roommate move out while owing me over $200. Sure, not a ton of money, but nothing to sneeze at, particularly when in grad school. He had left for the marines and told me a check was in the mail, but it never arrived. What a frustrating situation! I have had to loan friend and roommates money in the past, and every time it is stressful and I hate to do it. Five or ten bucks for lunch is one thing, $830 to prevent eviction was a different story.