I tend to agree with those who question why change the hydraulic fluid in RV's.
The Boeing 727 ran a 3,000 psi hydraulic system ( I think the newer transport airplanes are even higher) and the airline was strict regarding changing the fluid and filters based on operating time. But these are powerful systems.
Most hydraulic systems in TT's,FW's, Toy Haulers, MH's are far less powerful and run many less hydraulic components,so I also have to question the need to change the fluid.
I don't have an issue with changing the filter(s).