I do buy extended warranties on some of the tech items I buy. For example on my Roomba 980 I bought an extended warranty because Best Buy is pretty awesome at replacing things if they break and you have their warranty.
I bought a 2 year warranty and it's already giving me trouble. If iRobot releases a newer Roomba before the end of the year, I'll just shift my funds to the newer model, if not, I will get it replaced.
Same for my Fitbit, I use mine religiously and they get beat to death (bumps on walls, door frames, working around the house). When they get torn up, I just go to BB and get the next gen upgrade, paying only the difference and another extended warranty. The upgrades practically pay for themselves.
But that's where it ends i.e. on smaller tech items that get used
On Vehicles, if a car gives you a massive enough problem after X number of years using it, you're better off just trading it in for a newer model or a different brand all together. For me, that is piece of mind unlike having a large under-warranty repair and staying fearful of its potential return.