The big trick is to respect the people you live with, to have empathy for them, and most importantly to realize that in the long-term you are going to be a lot

The big trick is to respect the people you live with, to have empathy for them, and most importantly to realize that in the long-term you are going to be a lot better off if you adopt a policy of "I'll fix this as soon as I find an issue". That works especially because it keeps things from building to a point where they get to be an issue. And if an incompatibility is found/uncovered in this regard, the deal/relationship should be broken off (either the non-respecting/dysfunctional roommate is asked to leave, or the functional one chooses to leave). That's the only solution for Tragedy of the Commons, and roommates are one of the few cases where something can actually be done about Tragedy of the Commons. While it's often considered "fair" to split everything equally, I've found it useful to, for example, have one person's name on the lease and it's their place and can kick anyone out (if the landlord/lease is agreeable to that, depends on income and the rental market, really). For the same reasons outlined elsetimes on HN about how to split stock and voting rights between founders -- it's useful to have one place where the buck stops so as not to get bogged down in not being able to break a tie. If there's only one person's name on the lease, things are a lot easier (and often faster) to deal with when the relationship goes sour, for whatever reason.