Haven’t checked lately but I used to find the cost of extended warranties after 100K not worth it for us though sometimes we get road hazard coverage for our tires. (If we buy new, we have bought ext warranties based on our opinion of fair value. For example, the 100K plan for our truck that included was $750 but . . . we never had to use it.)
I’m a DIYer and forums like this, YouTube, combined with shop experience has been sufficient to get us thru most things. I realize the “big” stuff like engine and trans could be a huge cost but the think the chance of them failing is pretty low and keep on top on maintenance at severe service intervals. When the truck gets up there in miles, I might replace things like starter and alternators before they go out to avoid getting stuck on the road.