Think you’re safe from credit card fraud?  Think again.  You leave yourself vulnerable during the course of many everyday transactions-and you won’t know your number’s been stolen until fraudulent charges start showing up on your statement. Here are five ways we all leave ourselves open to theft when we use our credit cards.

Not using a card with a single-access number when you shop online. Some credit card companies offer cards that have an extra layer of security for online access.  Instead of giving the same credit card number to every online company you buy from, the company generates a new number each time you purchase-and lets that number stand in for your real credit card number.  This way, if identity thieves manage to gain access to an online store’s credit card records, the number they find won’t be yours. Companies that offer single-access numbers include Citibank and Discover.

Not checking your credit card statements. Not all fraudulent charges are large and obvious.  Some thieves could use your card for many small charges you’re not likely to notice right away. Always go through your credit card statements thoroughly each month and look for any charges that look out of place-no matter how small. If your identity has been stolen, this will help you catch the problem as soon as possible.

Not shredding your mail. Identity thieves often go through people’s mail to find personal information including credit card statements, birthdays, pin numbers, credit card numbers, bank account numbers and more. If you don’t shred all your mail, you are making yourself a target.  It’s not enough to simply rip your statements a few times before throwing them away-enterprising thieves can easily put large pieces back together again. Buy a shredder and shred everything you throw out.

Signing your card. Most people sign the backs of their credit cards. But believe it or not, it’s actually safer not to.  Sales clerks are supposed to check the name on your card against the name on your driver’s license or other picture ID if you don’t have a signature on the back of your card. While not all clerks remember to do it, some do-and if your card is stolen, you’ll be glad if someone checks.

Paying with cards at a restaurant. During most credit card transactions, your card never leaves your sight. But at a restaurant, the server walks away with your card-and there’s nothing stopping someone from copying down your credit card number and signature before your card is given back to you. To be safe, always pay with cash at restaurants.

There are many ways identity thieves can gain access to your credit card number. While it’s impossible to make your number perfectly safe, you can lessen your risk by taking a few simple precautions. Look for a single-access number card for online purchases, avoid using your card in situations where it will be out of your sight during the transaction, and don’t sign the back of your credit cards. Follow these simple tips, and you’re more likely to keep your card number safe.