I started a lengthy reply but nixed it. You have a truck chassis that needs maintenance similar to an auto. You can handle most of it if in good health and have a litle mechanical ability.
On top you have a large house. You can handle many repairs or all of them once you are familiar with them. That's the thing. If you've never done it it is intimidating and like rocket science to some. you can figure out all of the problems. Somebody built it and probably not any more intuitive as most RVers.
Get a good extended warranty. It cost but it is part of the cost of RVing.
newer coaches require less attention to roofs, and none to all electric refrigerators and so on. Do all your maintenance as in the manual, once a year and not worry about it. Break downs happen to most things. Just be prepared to deal with it. A good selection of tools for basic things.
Roadside Assistance coverage and warranty and extended warranty. Get them
Some say to save your money on extended warranty and handle out of pocket. Fine if that is you outlook and financial capability.
Just take problems in stride My antique was plenty of problems but the newer ones are light years more reliable.