I have my Cleaning Technologies slide-in with 23,715 hours. It is 27 years old. It runs better, and has more power in all departments, than the day it was new.
I bought it new in 1984, modified it in 1984 (larger silencer and added a separate muffler for the Onan 20 HP motor and routed the engine exhaust through the floor and under the van, to a separate sports car muffler, which exits in front of left rear wheel well).
Modded again in 1989 to run dual wands, including adding a second recovery tank, over-driving the Roots #45 blower, over-driving the Cat pump for more flow, and changed all the internal pressure lines over to 3/8" ID to accommodate more flow, and added a dual wand pressure manifold to the front panel.
More mods over the next 12 years, and in 2001 added a large LP boiler to replace the Little Giant 3HT. 3 years later I added our 220,000 BTU LP heater that we designed for our electric truckmount.
Just replaced the original Roots #45 3 years ago (original blower had 20,000 hours on it - would have lasted longer, but it lost the crankcase oil, and fried quickly), still using the original Cat 290 pump, and, the machine is now powered by a Honda 24 HP air cooled motor.
The main aluminum recovery tank is original (repaired twice over the years).
The machine frame is 2" square steel stock, not SS. The frame is as solid as the day it was made.
It is now ready for it's third van, which will include a good cleaning and painting, and a new marine grade 3/16" aluminum recovery tank with APO's.
There is no reason why you can't keep your truckmount for many years of hard use, if it is properly designed to be very reliable and easy to work on.
Every part on the machine is replaceable.