Credit cards can be useful financial tools when used responsibly but also carry risks. Paying with a credit card means the cardholder will be billed for purchases by the credit card company and is expected to pay the balance back. Using a credit card responsibly to make purchases and pay statements in full each month can help establish a positive credit history. However, only charging what can be paid back risks accruing expensive interest charges that make the total cost much higher if balances are not paid off each month.