Wallcovering properly applied will not come loose until you want it too. This is a subject that everyone seems to have an opinion on and mostly it derives from their grandmother's home or a session with a steamer loosening layers of old wallpaper. Todays product is designed to withstand high heat, humidity, cold, and dry environments. The trick is to follow the manufacturer's directions. When did your neighbor know better than the people who actually made the product? Do not add paste to a pre-pasted product, do use a good quality wall primer which is compatible with your wallcovering. Don't follow the big box clerk's advice go to a real store where they have knowledgeable sales people. I have wallcovering in our kitchen area, and bath. It looks great and does not come off the wall. The wall is more washable, will not absorb grease and best of all when we tire of the pattern it is dry strippable.
Good luck to you.
1994 30' Excella 1000, Chummy III- Ford Excursion- 7.3 Turbo-diesel