As sensible as it may seem to own a credit card for a store where you know the employees on a first-name basis, store cards can actually entice you to spend more than you normally would. "Most of the time, store cards like this come with a lower line of credit, so it doesn’t help your credit score very much," says Malani. "And you’d have to spend a significant amount at Sephora in order for the benefits to work in your favor. So, you end up spending more than you would have in the first place, and the excess spending negates your rewards or savings."