When you need to repair your car, refrigerator, computer, or a major system in your home, it’s comforting to think you won't have to break the bank to pay for the fix.

That’s why so many people are open to the idea of buying extended warranties that cover repair costs from the many companies that sell them.

These protection plans are also sometimes called service contracts or protection policies. But by whatever name, our advice is the same: Skip them.

Extended warranties can have many gotchas, relying on contract fine print to deny coverage for almost any reason. They've become a major source of complaints to the Better Business Bureau and elsewhere.

“Accidental damage may not be covered. And there may be clauses that allow the company to deny coverage if, for example, you don’t follow their instructions for routine maintenance,” says the Federal Trade Commission.

Extended warranties also can exclude a variety of parts. For example, among the refrigerator parts that aren’t covered under one home service contract we recently reviewed are icemakers, beverage dispensers, door seals and gaskets, hinges, lighting and handles. An auto service contract we examined excludes brake drums and rotors, air bags, door handles, lock cylinders, the exhaust system, body panels, among other parts.

Can you demonstrate that the troublesome part wasn’t already broken when you signed up—a so-called preexisting condition? Was the problem caused by a manufacturing defect or by an accumulation of sentiments, rust, mildew or mold? Is it a cosmetic issue that doesn’t affect an item’s performance? All of these can be reasons why a provider will reject your claim.

Washers and dryers are seen on display at a store in New York Thomson Reuters Some extended warranties simply duplicate the express warranty coverage you have the manufacturer, which you’re required to use first.

And along with the initial cost and deductibles, some plans charge a fee every time you make a claim.

If the plan allows you to use your own repair shop, as with many auto extended warranties, the shop typically has to obtain approval from the provider before beginning work, a big hassle that some shops might consider too much trouble.

Yet another concern is that providers can go out of business, leaving customers without the coverage they paid for, warns the FTC. That’s a particular issue with third-party extended warranties, as opposed to those provided by product manufacturers.