BOSTON -- If you're thinking about keeping your car longer, you may also be thinking about the cost of repairs. Here's what you need to know before you buy an extended warranty.

An extended warranty is an insurance policy and, so, a gamble. You buy it hoping you don't need it, but you want to make sure the coverage is there if you do.

Where Should You Buy An Extended Warranty For Your Car?

Extended warranty offers come through the mail, e-mail and even online pop-ups from a variety of companies, most of which require that you pay in full upfront.

But NewsCenter 5's Susan Wornick said she routinely hears complaints about companies selling policies only to disappear when asked to pay a claim.

Extended warranty sellers are not regulated. They don't have to be licensed. In fact, they don't have to register with anyone to do business, so you're stuck if they take your cash and go out of business.

Protect yourself. Buy a warranty through a car dealer and only from the manufacturer. Salespeople sell a variety of products and make different commissions from each, so don't let them influence your decision on which company to use.

The car manufacturing business isn't as strong as it use to be, but your manufacturer is less likely to go out of business or disappear with your cash than a company you don't know.