It's really for emergencies. In this case, we define an emergency as any time you need money now, not a week from now. This means NEED money, not WANT money. If you have bills or rent you don't want to be late on, that's obvious. But you might also want to snag something on eBay before another bidder does, who knows? Just don't borrow for anything that won't still be available to spend money on in another week or two. It's for when you need money NOW, not for when you need money either now or a week from now.