Even people who can pay off their credit cards often don’t, since the whole structure of the credit-card industry is designed to make you irresponsible—as long as you make a small monthly payment, the bank will carry you. In fact, that’s what the bank wants: the profits in the credit-card business come from "revolvers," people who pay a small amount each month and rack up big interest charges—far more than the five bucks they’d have spent on a layaway service fee. Layaway, by contrast, fosters virtue: it forces you to save, because if you don’t make the payment you don’t get the product. It’s what psychologists call a "commitment device," a way to get yourself to do something that you want to do but know you’ll have a hard time doing if left purely to your own devices.