Zero. It's the dumbest idea I ever heard.
Zero. It's a good idea, but I'll take my chances.
$10-$20 per year. Good idea, and at that price it's a no brainer.
$20-$50 per year. Good idea, and at that price it's a good warranty buy.
$50-$100 per year. Good idea. It's a bit pricey, but worth it.
Forget this per year stuff. Just add something to the purchase price and call it an extended warranty.
