My general rule is don't buy them, but I make an exception for kids' electronics.
if you buy with Amex, does it extend by 1 year?
The rule of thumb is: DON'T. Period. It's a loser for the consumer and a huge money maker for the seller. Always buy with a credit card to get the warranty protection that offers.
General rule is whatever you base it on the person issuing it has already done the math and will come out ahead. Thus normally don't get one.
I think there are clear exceptions. Bestbuy for example offers warranties based not on brand but on price. Therefore, a $1000 TV from Samsung costs the same for warranty as one from a crap brand. I think it makes more sense to consider it for the crap brand, assuming the issuer has done a cost-risk and blurred the lines across all TVs at a given price point.
I think it is a good idea to buy a warranty on a new console as well, considering their failure rates seem to be very high, but the manufacturers do not jack the warranty prices early on in a generation accordingly; I think they make far less money on their warranties early than later one when failure rates are much lower.
Why would one want to replace an extended warranty?If your TV/electronics are going to go bad then it tends to be soon after you get it. Extended warranties aren't worth it unless maybe there's no way you could afford to replace it. But if that's the case you should be buying a smaller TV.
I had never thought of that. Is this a fairly common credit card feature, or is it only from a few select cards?
Cost.
I just bought a tv that came with a 1 year warranty. I purchased a 3 year extended warranty that starts after the manufacturers warranty ends. It was $99 at Costco through SquareTrade.
For cars, always. For gas powered snow blowers it may be a good idea also. For everything else, no.