h2g2 The Hitchhiker's Guide to the Galaxy: Earth Edition

For everyone's sake- please get the bills sorted out before you move in.
Work out who is paying for what, and stick to it. Split the bills down the middle, if you have to. Nothing can ruin a relationship faster than arguing about money. Possibly apart from having sex with your partners parents.

I agree about the bills, although halving them seems a bit unfair if one person earns more money (people in a relationship, obviously - flatmates isn't really the same thing). I've always thought that the fairest way is that if one of you uses the phone/internet/etc more than the other, then they should pay that one, even if only so the other one can't moan. But generally, if you both pay the same percentage of your income over to communal living, then that's a bit fairer. If that makes sense. Unless one of you has a child. The income related to the child should really be used for the child (and for a few for the stressful times), and not for going out partying with.