Some people spend more money, either by purchasing more items or by purchasing more expensive items, when paying on credit than they would with cash. Purchasing a $1,000 laptop might be easy to accept if you just sign a piece of paper. On the other hand, if you pay with cash, you can physically feel the $100 bills leaving your hand. This will give you a better sense of not only how much that laptop truly costs, but also how much money you have left in your now-lighter wallet.