They should be worth it because they can be expensive. Federal laws say warranties must be truthful and deliver what they promise.
But one Bay Area teacher told 7 On Your Side her no lemon policy left a sour taste.
Danielle Adler's laptop has turned her sixth grade classroom into a high tech learning lab. She loads it with materials and instantly, it becomes an interactive blackboard.
It is a modern way to learn ancient culture with basic lessons and learning games.
So you can imagine how devastated she was when her computer died whatever works best right before the school year started.
"Before it even turned on an alarm sound, it was like a beep, beep, beep," said Adler.
And it wasn't the first time. Danielle had taken it back to Best Buy for repairs several times before.
So she sent it in again and when it came back, she turned it on in the store. The screen was totally blank.
"The same alarm went off," said Adler.
Danielle pointed to the Best Buy service plan she'd purchased for $360. It has a lemon policy stating that: "After three service repairs, if a product requires a fourth repair, the consumer gets a new one."
And this, she said, was the fourth repair. But Best Buy said its records showed only one previous repair.
"I said that's impossible. I was shaking I couldn't believe this was happening," said Adler.
Danielle whipped out her records proving past repairs. And with that Best Buy gave her another laptop. Danielle wanted 7 On Your Side to hear the story, so we could pass the information along to you.
We checked in with Best Buy best buy which told not all repairs count towards its lemon policy. For instance service for software problems and dead batteries don't count towards a new computer. Best Buy still says Danielle didn't have four qualifying repairs, but it gave her a computer anyway because "customer satisfaction remains a top priority."
Danielle's class is now back at the computer -- back learning again.
The Better Business Bureau says it has received about 1,500 complaints about Best Buy warranties, and about half were resolved.