I remember reading sometime ago of a bad experience of somebody buying a computer from Best Buy and then her mouse broke. She tried to claim on the warranty but was given the runaround. Finally, when she convinced the shop to fix the mouse, it took more than 6 months to get it "fixed".
This story shows that we should not waste money on unnecessary warranty. However, from my own experience, I found warranty and extended warranty to save me on several occasions.
Warranty saved my butt
I bought an Axim x50v a couple of years back and had extended the warranty to 3 years. The PDA died within days after its 1 year anniversary. However, with the warranty, I was able to get a replacement. The unit cost me RM 2K/- at the time.
In another case, I bought a Samsung LCD monitor. At the time, they had a promotion and came with 3 year warranty. Again, a few days after its first year anniversary, it just went black. This time the distributor claimed it was out of warranty. Luckily, I still had the warranty card to prove the 3 year warranty and the unit was repaired (unfortunately, it died after its warranty).
In another case, I bought a Dell Dimension 5150, with this I bought a 3 year extended warranty. With the warranty, I was able to call Dell support at 11 pm at night and arrange for the technician to come to my house to fix the computer after work (at 8 pm) at night. Only catch is that when the unit was delivered, they provided you with a number to call in. This number is not listed anywhere in the dell website!!
It's your Responsibility
One thing to be aware about warranties is that it is your responsiblity to remember its validity. I had a case where I bought a Siemens handphone. After 10 months the LCD suddenly went black. I forgot to check on the warranty and took it back to the shop to fix.
He told me it would take a week. That night, I looked for the warranty card and found that it was still under warranty. However, when I called the shop they said that they have already sent it out for repair and that I could not claim the warranty anymore. Subsequently, when the phone was returned, I found other problems.
The shop insisted that the problem was not caused by them. However, after some argument, they agreed to try to fix it. That is to send to the distributor in another state to reload the software. At the end, it took them more than six months to get it fixed. During that time, they were "nice" enough to loan me another old phone to use. Sadly, I lost the phone two weeks after I got it back :( However, due to my experience with them, I swore off that shop for good!
Sometimes you have to Ask
One of the things about warranty is that they never tell you how to get it. HP makes PDA phones and sell its through resellers. Standard warranty is one year. In order to extend the warranty, you need to contact HP within one week of your purchase and then buy the extended warranty. After that one week, you are out of luck and stuck with only one week warranty!