Your credit card provides you with valuable purchasing power and extreme convenience. To purchase an amazing number of goods and services, all you need to do is present your card and sign a receipt. Unfortunately, this power and convenience also make your card that much more appealing to criminals looking to take advantage of your credit.

Your Card and Account Number

Guard your card as you would the key to your home. When receiving a new or replacement card, sign the back immediately. Keep it and any duplicate cards in a secure place where you would know if they were missing.

Never leave your card with someone as a "security deposit." And if you're expecting a new or replacement card, keep a sharp eye on the mail.

Since a thief can just as easily make purchases with only your account number and expiration date, it's a good idea to take all receipts and carbons with you, especially from places like automated teller machines (ATMs), supermarkets, and self-service gasoline pumps.

Avoid disposing of purchase documents or old statements in public trash containers, and never give your account number to someone calling you on the phone - even if the caller says it will be used to claim a valuable prize or award.

Your Personal Information Should Always Be With You!

Your personal information should always stay with you. With the exception of mail order companies, merchants should never require your address or telephone number to complete a transaction.

Avoid using your card as personal identification. Never let someone put your card number on a check or any other document not associated with a purchase on your account. (In some states, it is actually against the law for merchants to do so.) Use your driver's license instead.

If your account has a personal identification number (PIN) for use at ATM locations, don't write it down: memorize it. And it's a good idea not to pick an obvious PIN, like your address, phone number, or date of birth.

Limit Your Legal Liability

If your card is used before you report it lost or stolen, your maximum liability for unauthorized charges is $50 per card. If you report your card stolen before someone uses it, your liability is reduced.

If a member of your immediate family (spouse, child, parent) borrows your credit card to make a purchase - with or without your knowledge - you may be liable for that purchase.

Don't forget to notify your card issuer if you and your spouse become separated or divorced. Otherwise, you could be liable for charges on your joint account.

Review Your Statements Carefully!

Billing errors can happen. So it's important to save your receipts and credit slips and compare them to your monthly statements. File your statements in a secure place for future reference. If you don't keep your statements, destroy them before throwing them away.

If you do discover an error on your statement (like an unauthorized charge or purchase), write to your card issuer immediately. Be sure to state that it is a billing error, which is handled differently than a dispute with a merchant.

Remember: You must notify your card issuer in writing to be legally protected. Also, it is far more difficult to challenge a charge once it has been paid.