Schools, phone companies, utility companies, health care providers, health clubs, insurance companies, video stores -- just about everybody wants your Social Security number. Why? Usually it's because they want to check your credit rating to find out how you handle your bills, and to keep track of you through name and address changes.

But companies also use your number to develop marketing lists, which they can sell to other companies. A list with the numbers is more valuable than one without.

Unfortunately the more people who see it, the more susceptible you are to identity theft.

While any business or agency can ask for your number, few can actually demand it -- motor vehicle departments, tax departments and welfare departments, for example. Also, SSNs are required for transactions involving taxes, so that means banks, brokerages, employers, and the like also have a legitimate need for your SSN.

Most other businesses have no legal right to demand your number so take your business elsewhere if they insist on writing it on your check.

Don't carry your Social Security number and driver's license together in your wallet. And avoid using your mother's maiden name or the last four digits of your SSN as a personal identification number or password.

-- Compiled by Dani M. Arthur, illustrations by Brandy Kesl

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