I just replaced my Fourth AC on my 2005 Fiver.
Most recent two ACs lasted only 5 and 6 years. Both were installed at the same time.
The Coleman Mach Low Profile 13.5K Bedroom AC that wasn't used that often lasted only 5 years.
The Dometic Brisk Air 15K Ducted/Main AC lasted 6 years.
We do use / live in our RV about 9 months per year (in the Summer or South TX for the Winter which means AC is used a LOT) so for most RVers won't have to replace so often, but I wonder how this might compare to Fulltimers...
Also replaced the OEM Suburban Furnace last Fall as the Blower got noisy. New Furnace is much quieter.
Glad I can fix most systems on the RV myself...
Retired USAF
Silver 05 Dodge RAM LB CTD Dually 4Speed Auto SWD 3.73, Westin Sportsman Grill & Taillight Guards,Husky Mudguards, Retractable Ball Hitch, Onboard Air & Horns, MaxBrake - towing 2005 Keystone Montana Big Sky 3670 with Star Performance adapter