I'm renting and probably paying the landlord's mortgage. But I know that I will live here a specific period of time and then move. So by renting, I'm buying peace of mind: I don't have to sell a house or worry about getting stuck with it, and I don't have to add a mortgage to my other debt.

When I'm going to be somewhere long-term, or at least have a flexible schedule for moving away, I'll want to buy.