You are the exception, certainly not the norm.
I haven't been buying the wrong anything. I've done OK with my trucks and trailers, though my last Superduty is falling apart. I wrote this to give newbies a heads up.
This guy is a great example of what happens when you rely on others to work on your RV. He'll do little stuff, but when it comes to anything major, he runs to Freightliner and pays the price. He spent over $20K the first 2 years of owning his used coach.
https://www.youtube.com/watch?v=i1AH8jD4zR4
https://www.youtube.com/watch?v=QM8XDmjNDpQ
https://www.youtube.com/watch?v=7j98e3bd01Q
https://www.youtube.com/watch?v=f2IymWQEBns
