As pizzadude said make sure you understand the details of what is covered and not, but after that you need to look at it as an insurance policy of sorts. I had one that paid for several thousand dollars of repairs (6K+) including rental car during the repair and it was well worth it. The extended warranty on my current vehicle just ended with no claim during the four years. But the peace of mind was worth the cost to me. If it has a major problem at this time it's on to the next vehicle since this one is paid off.
Most financial gurus will tell you that extended warranties are a losing proposition and as MVV said you should just have an emergency fund to pay repairs. But I'm not that disciplined and I'll pay for the insurance and peace of mind. BTW both of mine were purchased through the selling dealer at the time of financing. I am aware you can get cheaper after market deals. I just didn't want to spend a lot of time comparison shopping.
Starting Score: 500's
My wife bought a car from Nissan in S. Cali in August and they used a $4200 service and maintenance warranty to get the deal done because she was far upside down on her ford escape. We knew what they were doing and went with the deal and knew if we objected the deal wouldn't get done. Less than 30 days later we went back to the dealer and attempted to cancel the warranty. The finance mgr or whoever did her paperwork that night said this deal was done on "good faith" that we wouldn't cancel and to get the deal done we had to do it this way(wouldn't honor the request to cancel). Had 60 days to cancel the contracts and on about the 53rd day (Oct 3rd or so), I wrote one letter to the local dealership and Nissan North America who sponsors the warranty stating our desire to cancel. Sunday we were looking at her online statement from Nissan and there was a $4200 credit to her principal balance. The actual letter from Nissan in Tn came yesterday.
Bottom line, no I would never get an extended warranty. In our situation, from what I understand, something about the commission is charged back (they loose the commission on that sale).
That was risky business! 