Don’t charge more on your credit cards than you can pay off at the end of the month. Revolving credit is the worst kind of credit. Credit cards are designed so that you charge purchases and then pay them off, not so that you can charge purchases and keep charging. Most of my clients can only afford to make minimum payments on their credit cards. At that rate, even if you stopped using the cards, the balance would grow exponentially. Make sure you can afford to pay for what you charge as though you were spending on a cash basis.