A relative of mine was dithering about renewing the factory 'extended warranty' on his Mercedes as he didn't want to spend the ~$5K 'on a car that old'. He couldn't imagine that his car would ever incur high repair costs, even though it had had some expensive repairs under warranty and (discounted) extended warranty before. Everyone was telling him he was being an idiot and pointing out surveys and forums saying that it was stupid to own this car without it. He said this couldn't be the case, used many of the arguments against the warranty that people used higher up on this very thread. He almost missed the renewal window and paid the money on the last day. Grudgingly. While complaining loudly and bitterly, and grousing for weeks about the 'unnecessary expense'.
Six weeks later, the in car entertainment system in the center stack, which included the climate controls, navigation, phone controls (mandatory hands-free state) and more, decided it was a good time to die. A couple months after that, the engine's cam position sensors and related harness failed in the middle of a *very* unpopulated area.
Total cost covered by the extended warranty in less than six months, $21000.
Need I say more about how this was a good idea?
An extended warranty on something like a Toyota pickup is probably going to be pointless or at least a poor value proposition - but anything with appreciable levels of complex, expensive technology of unknown or questionable reliability? Yeah, that's a different story. On this particular car, prior to this incident, the extended warranty had eaten $15K worth of costs.
Before deciding whether it's a good or bad idea on a car, go look up common problems with the car and the cost to fix. Even if it's a car you had before and the suspect systems haven't increased in tech level or complexity, it's a good idea. I am going to have to have a GM transmission rebuilt for the second time in about 12 years. The cost to rebuild it last time was $1150, tow in/drive out. Today that rebuild is going to cost about $2800 due to increased labor rates in my area and overall cost. Same parts and same shop, happy with both and the shop isn't ripping me off.
Just because it cost $X to repair something ten years ago doesn't mean that it still costs $X now - it's always a good idea to update your mental database of potential costs.