I am the mehcanic on my motorhome. I'd go broke if I had to write a check everytime something went wrong.
I have a Diesel, but I do my own oil changes. All the stuff can bought at Walmart and the motorhome oil change is easier than any of the cars that I own. Although I run Synthetic in my cars, I run the old Dino juice in my motorhome.
The main reason: I don't drive more than 7,000 miles in a years time, so Synthetic would be a waste if I were to toss it early. I change the oil just prior to winter storage because I don't want oil that is contaminated with a seasons-worth of moisture.