Extended warranties?? That's something that each person determines based on their personal experience, tolerance for risk, mechanical ability, financial situation etc.
Are they worth it? Not at all....unless you have a $10,000 misfortune...that they would cover. You also should have RV insurance that would cover some things. The extended warranties also require some sort of inspection/repairs done by someone, usually a dealer, at set periods of time. If you don't want to do those then it would probably be a waste of money IMO. If you want to stay on top of things, usually use a dealer to do those things and keep records the warranty COULD prevent a very large dent in your pocketbook.....only you can decide......