You may have other warranty rights. As a result of state laws, most products automatically come with an unwritten "implied warranty of merchantability," which means the items must function as a person reasonably would expect, be free of substantial defects, and last a reasonable amount of time (although the duration of the implied warranty usually is no more than four years). If a product can’t meet these requirements, you may have a right to pursue the retailer and/or manufacturer legally. An exception is allowed for items that were sold using terms such as “as is,” which is the case for much of what’s being sold online, based on the fine print we’ve read on many retail websites. But 11 states (Connecticut, Kansas, Maine, Maryland, Massachusetts, Minnesota, Mississippi, New Hampshire, Vermont, Washington, and West Virginia) and Washington, D.C., prohibit such exceptions, so you’re covered no matter what. For more information on your warranty rights, read our 2013 report, "What you need to know about warranty laws."

The Plan May Let You Down

Service plans typically have many fine-print exceptions that a provider can use to deny your claim. Among respondents to our 2015 survey whose repairs were covered by extended warranties, 61 percent were highly satisfied and 19 percent were dissatisfied with their repair. These numbers are similar to the percentages for those who paid for repairs out of pocket. Fifty-five percent were highly satisfied, and 21 percent were dissatisfied. Our surveys also found that:

• Seventeen percent of those who had an appliance repaired under an extended warranty said it took an unreasonable amount of time to get it fixed, compared with 9 percent of those who paid for the repair out of pocket.

• Twenty-three percent of those who had an appliance repaired under an extended warranty complained that it took more than one try to get it fixed right, compared with 15 percent of those who paid for a repair themselves.

Automotive service plans sold by third-party companies instead of by car manufacturers have been a particular problem. There have been many complaints from customers who say the providers often refuse to pay claims, often saying the problem isn't covered.

You Can't Afford to Protect Everything

Even if the plans were worth every penny, it's simply not cost-effective to buy a plan to cover every major purchase in your life. While a service plan may leave you coming out ahead once in a while, overall you'll probably save money by avoiding plans and seeking other ways of tackling broken or defective products.