In recent months, major retailers like Amazon and Target have announced new partnerships with trendy BNPL startups like Afterpay, Affirm and Klarna, giving shoppers the point-of-sale option of splitting the cost of purchases into equal installment payments spaced out over a predetermined period of time. 

But while these plans offer more flexibility to consumers who might balk at paying full price upfront, experts say that BNPL can easily lead to overspending—especially over the holidays.

“Buy now, pay later has changed the perception of money and how we handle money,” says Elin Helander, Chief Scientific Officer of financial wellbeing startup Dreams.“ The idea is that if there aren’t any fees, why pay now if you can postpone and it doesn’t cost extra? But what happens is that you’re more likely to forget how much money you’ve spent, so you overestimate how much you have left.”