Cost of things! Google cheap and you will find my picture. I dislike staying in hotels and detest using public bathrooms, the real biggie is I like to take a nap when I want to. So I spend the money.
I have a 94 Toyota and if I had to pay people for repairs I would have to let it go and stay in hotels, and nap in the car. Repairs are not bad enough, then there are the dishonest shops. I wanted to get a AC expansion valve replaced 3 years ago and took it to the local AC place as I did not have time to mess with it. They gave me a $1200 estimate. TWELVE HUNDRED US DOLLARS. So I changed plans and did it myself, total cost less than $100 and at most 4 hours work. This is fresh in my mind as here it is 3 years later and I am in the middle of replacing the valve again.
I full timed for 10 years and was able to live very inexpensive even with the loss of about $40,000 when I sold the RV. That was a bus conversion I had built myself, sweet machine. Things I learned, the friends I made doing that and the experiences of RV'ing I cannot put a dollar amount on.
Being cheap is tough, sometimes I do myself a disservice by trying to save a $, I have to watch that. You know that feeling you get when realizing that $12 was spent on gas to save $8 on a campsite.