things with moving parts (motors/engines) MIGHT be worth considering an extra warranty, but if a piece of electronics is going to fail prematurely it is generally going to fail in the warranty period, assuming a typical one year warranty and that you actually use it a lot.
I almost never buy extra warranties, but the two times i did, i use it. One was a humidifier i ran all day, every day, outside my newborn kids' rooms all winter that failed that spring. And the other was Apple Care for iPhones that my wife and I bought … we thought that the kids might smash them. Turns out that my wife's phone's wifi went to crap and she got a new iPhone for free.
neither of my Canon cameras have had extra warranties, and both are still running strong. If you are going to be bonking your camera around a lot, or are just a complete klutz, you might want to consider it.
PSA: The above post may contain sarcasm, reply at your own risk | Not in gear database: Auto Sears 50mm 2.0 / 3x CL-360, Nikon SB-28, SunPak auto 322 D, Minolta 20