Void incorrect receipts. Save receipts to compare with billing statements. Open bills promptly and reconcile accounts monthly, just as you would your checking account. Report any questionable charges promptly and in writing to the card issuer. Notify card companies in advance of a change in address.
Thieves closely watch mailboxes of recent move-outs for mail left behind.
Don't lend your card to anyone, leave cards or receipts lying around, or write your account number on the outside of an envelope. When you sign a receipt, draw a line through any blank spaces above the total. Check the math total. Don't give account numbers over the phone unless making the call to a company you know is reputable. If in doubt, check it out with your local consumer protection office or Better Business Bureau.