I figure that the extended warranty companies are in it to make money for themselves. They don't particularly care about you the owner.
I have been rolling around the country for over 10 years & have had over 200,000 miles pass underneath me. The trailer has had an average of some 150 nights use each year. You could say that all systems have been used alot.
No extended warranty here though I do figure on $2000 a year on maintenance, including tires as needed, for the trailer. Don't think that I have ever come near that figure except the year we had to replace the out of warranty fridge. Ouch! Same with the truck. Figure $2000 a year for maintenance, including tires but not oil changes. Almost everything over the years has been routine wear items. Bushings, shocks, seals, hoses, that sort of thing. Only been over that $2000 figure for the truck a couple times.
Have to wonder, how much would an extended warranty have cost & how much of all that routine maintenance would have been denied? I think lots of money has stayed in my own pockets.