The proliferation of these instruments — buy-now-pay-later schemes attached to ordinary household purchases, point-of-sale loans for groceries, four-payment plans for a pair of shoes — strikes me as a development that warrants the attention of every working household.

I am not, in principle, opposed to credit. The merchant's bill of exchange has, for centuries, allowed honest commerce that would have been impossible without it. What I observe is that the new instruments break the old discipline. The borrower who took a six-month loan from his banker had, of necessity, to sit across a desk and account for his prospects. The borrower who clicks a four-payment plan at checkout has no such interruption to his enthusiasm. And it is precisely the interruption to enthusiasm that distinguishes prudent credit from the slow disorder of debt.

My counsel, for whatever it is worth, is the older one: account for every expenditure for one month. Not because the accounting will reveal great extravagance — most households are honest with themselves about the larger sums — but because the small monthly installments, scattered across a dozen merchants, are the leak. A pair of shoes at twenty dollars a month is a friend. A dozen four-payment plans, each forgotten, is a slow theft from the household's future.