If you have no hesitation about using your card, but are equally disciplined in paying off any balance each month, then you can take full advantage of the effective "interest free" period between purchase and each monthly settlement date. On most cards, this will allow you a reasonably long 59-day period of grace – though there are some which grant a shorter period, and others which allow none at all, so you would need to be careful to avoid these. For such careful credit card users, moreover, there is also the chance to gain more by selecting a cash-back or reward card that wins you some of your money back or "free" gifts every time you use the card. Alternatively, you might prefer a card that donates a proportion of your spending to the charity of your choice.

If your best intentions are not always fully met and you find that there is an outstanding balance sometimes carried over from one month to the next, then interest on your credit spending will of course begin to mount up. It is now that you will need to take more careful note of the interest rate applied by the credit card provider. And it is here that the picture gets rather more complicated. There is a huge range of different credit cards available – and a huge range of interest rates to go with them. What is more, the difference between those rates can also be very large – more than a 10% difference in the annual percentage rate (APR), for example. The differences will be affected by such factors as the differences in standard, basic rates of interest; the period of grace between purchases and application of interest; those offering an introductory interest free period on purchases; those offering interest free balance transfers; and those offering cash-back, reward or charity schemes. When comparing rates, therefore, it is necessary to take all of these factors into account and decide which, if any, are suitable or desirable given your own spending patterns.

If you are the type of credit card user who knows that there will always be an outstanding balance on the card at the end of each month, then the rate of interest will be critical. In this case, you are likely to put to one side any of the extra frills and trimmings and go solely for a card with a low standard rate of interest and perhaps kick things off with a card that offers an introductory period (of typically up to 6 months) completely free of interest.

If you have already built up a sizeable debt that you want to clear, a golden opportunity to do so is provided by the many offers of zero-percent interest balance transfers. These will give you a fixed period (typically six months) on which no interest is charged on the transferred balance, so represents the ideal time in which to clear it. Some cards will also extend the interest-free arrangement to any new spending on the card during this period – though unless you are also paying off such expenditure, it will of course be added to the total amount outstanding. Still other cards might offer zero-interest on the transferred balance, but charge a higher than standard rate of interest on any new purchases. The message once again, therefore, is to examine very carefully whatever is on offer and ensure that you sign up only for the credit cards that match your particular needs and habits.