Errors on your credit reports might mean you could be denied credit or be offered higher interest rates than you should be. They could also mean you'll pay more for auto insurance or be denied a new job.

The Consumer Financial Protection Bureau (consumerfinance.gov) says it soon plans to begin oversight of the largest credit-reporting companies, including Equifax, Experian and TransUnion. You can access your reports with the three main credit-reporting agencies online at annualcreditreport.com, or call 877-322-8228. By law, you can retrieve one free report a year from each of the bureaus.

More important? Check your reports, no matter which way you do it, said Liz Weston, author of "Your Credit Score" (FT Press, $19.99). "Looking at them all at once is better than not looking at all," she said.

Some 96 percent of free reports go unclaimed, said John Ulzheimer, president of consumer education at SmartCredit.com

If you find a mistake on your reports, here's what to do:

Determine whether it's serious. If a street name where you lived three homes ago is spelled slightly wrong, don't sweat it. It is unlikely to affect your credit. If you see a credit account you never opened or indications of late payments or a bankruptcy that aren't yours, that's a big deal.

File a dispute, Part one. Dispute the error directly with the credit-reporting agency. If wrong information appears on more than one report, dispute it with each credit bureau.

Dispute by mail. You can file a dispute online or by mail. Online is easiest but not the best, especially if the report has a serious or recurring mistake, credit experts say. .

By filing in writing, you can fully explain the situation and include copies of supporting documents, such as canceled checks or court documents

Keep records. Send your letter by certified mail, "return receipt requested," so you can document what the credit-reporting company received, advises the Federal Trade Commission on its website. Keep copies of your dispute letter and enclosures.

What happens next? Credit-reporting companies must "investigate" the items in question, usually within 30 days. Most times an investigation means the bureau asks the creditor if the disputed information is correct.

File a dispute, Part two. If your efforts to correct a mistake fail through the usual process with the credit bureau, you can try again, but unless you provide different information, the result is likely to be the same, Ulzheimer said. The next step is to dispute the negative item directly with the creditor, often a bank.

Again, disputing by phone is easier — the bank's phone number is on your account statement or the back of your credit card — but disputing in writing gives you a paper trail that might be useful later. (It's important to go through the credit bureau first. If you instead file a dispute directly with the creditor, they are not obligated under law to do anything until you first dispute it with the bureau, Ulzheimer said.

Get an attorney. If you can't persuade the creditor to change the information, hiring a lawyer and potentially filing a lawsuit is your last resort.

Sometimes all it takes is a stern letter from a law firm, Weston said. She suggests checking for lawyers with the National Association of Consumer Advocates, at naca.net.

What portion of credit reports contains errors? A study by the U.S. Public Interest Research Group suggests it could be nearly eight out of 10, but a group funded by the credit industry says fewer than one in 100 have serious errors.

Know your score

Your credit reports are the basis for your credit scores.

If you want to see a score most similar to what a lender is likely to see — if you'll be applying for a mortgage, for example — go to MyFico.com and pay for either your Equifax score or TransUnion score. (You can't buy your Experian score anymore.) FICO Standard scores cost $19.95 each.

If you're just curious and want a general idea of where you stand, you can retrieve free non-FICO scores at such sites as CreditKarma.com, Quizzle.com and CreditSesame.com.

Ignore sales pitches for monthly credit-monitoring services on the sites.