Some don't bother...
I know many, many people who prefer to tear it out and paint.
Personally, I like the quiet coziness of my carpet-like headliner, even if it is a bit stained from old leaks from previous owners...
My buddy is staring down this task on his Beneteau First 235. I told him about the article in one of the sailing mags a few months ago (might have been Sail) where they made a funny "self help"-like article where they say stuff like "You may be tempted to use spray adhesive to postpone the inevitable. It will not work for long."
I told my buddy he's just going to have to tear it out, and live with the hell of trying to clean off deteriorated foam and old adhesive.
Sometimes I wonder why they use foam backed vinyl, when they know that the foam is going to fall apart eventually. Well, I guess it looks nice at first, and lures people into the cabin, and is easy(er) to do at the factory, and they know it will fail LOOOOOOONG after the warranty expires, so why not?
Brian
I just completely tore out the entire hull liner of my O'Day 28, scraped the foam off down to the fiberglass, and replaced it with foam backed vinyl I purchased online from DEFENDER. It was a very arduous task and took many hours, but I am delighted with the results.