I see queries along the lines of "I'm think about buying ... what does it cost to maintain" or something along those lines.
When pondering such questions, I am reminded of the response made to such a query about Private Aircraft maintenance costs sometime in the early '70s by Richard Collins editor of Flying Magazine. I can't remember the exact way he said it but this is the essence of his message: When you buy a used Airplane for $25,000 whose cost was $150,000 [1970 Dollars] when it was new, don't expect to pay same the maintenance costs as you would for a new $25,000 [1970 Dollars] airplane. He went on to comment that you need to figure a percentage of the original, when new, cost as the basis for how much you will be paying for maintenance.
I believe this generalization holds up for Motor homes too.
So, how do you answer a question like: I am thinking about buying 1999 ABC used Diesel Pusher and I was wondering how much it more it would cost to run than a later model gas powered Class A XYZ that I could get for the same money?
I'd respond: in a rough ranking of maintenance costs against a Class A Diesel Pusher (DP) that:
a Gas Class A is about 3/4 to 1/2 of the DP cost to maintain;
a Class C would be about 1/2 to 1/4 the DP cost to maintain.
Why? It's all about the cost of the components. To some extent it is just like buying hamburger by the pound. The higher the GVW/CGVW of the Motor Home, the more you pay me now and pay them later.
--Class A Diesel Pushers use limited production, purpose built, medium/heavy duty truck & bus components (expensive), most of which have to be adapted in some way for Motor Home use. Because of this they require specialized facilities and mechanics to work on them.
--Gas Class A Motor Homes have a conventional front truck engine but access is limited, their transmissions are high volume pick-up truck based (high volume, lower cost). You can probably put FREDs (Front Engine [End] Diesels) in with this group.
--Class C have a conventional front truck engine and transmission, conventional suspension systems, smaller tires (all high volume, lower cost) and you can get them serviced at most Ford, Chevy or GM dealers.
As a group, we undo the reliability of the heavy duty components in a Diesel Pusher by not driving them enough. Just like my Airplane example, unused Airplanes and unused Motor Homes don't make their stated time to overhaul. DP would make their million miles to engine over haul if we drove them a million miles in ten years, but most only get to ~100,000 miles in 10 years. How many buyers think twice about buying a 10 to 12 year old DP with over 100,000 miles or over 600 hours on the diesel genset?
There are always exceptions to these generalizations. For instance:
-Jayco medium truck based Class Cs aren't exactly your standard Class C, they are more like a Class A FRED.
-Some of you are capable of doing your own work on your RVs, even DPs.
-Some of you actually do wear out your equipment by driving them and those few of you do it experience a lower cost per mile of maintenance expenses.
-Frankly, I don't know how to rank Mercedes Sprinter based RVs.
So, what do you think about this approach?