Conventional wisdom says not to buy extended warranties because they are usually a waste of money. Usually if something is going to go wrong, it will happen while it is still under the manufacturer warranty or by the time it does, you might want an upgrade anyway.
There are exceptions of course. I bought a 2 year extended warranty on my grill which expires on the 17th. I read some online reviews that said that certain parts tend to rust out or need replacing and the cost of the parts is more than the $40 I spent on the warranty so win.