My trailers been out of warranty for over 10 years now... Other than regular maintenance stuff and whatever minor things I've fixed over that time, nothing major has happened to me..
If an extended service contract makes sense for you, go for it... I'm sure there are many places that would love to sign you up! ;)
Just be sure to read the very fine print on claims to be sure you understand all of their policies.. Biggest one that I see happen to folks is they don't get 'pre approved' for a repair because they are out on the road and essentially stuck until they get whatever broke fixed... They get it fixed and try to turn in the claim and are denied because they didn't get 'pre approved' for the repair.....
Anyway, good luck with whatever you do!
Mitch