Soren, I think you have made a good point. It's not mileage alone that a person should look at.
The condition of the interior is very important. If the insides are equal on two similar units with one having high miles and one with low miles, a unit with the systems that have been exercised would, to me, be better (I don't mean worn out).
I exercised our coach drive-train and systems monthly. Did things need repair over the years?, sure. I had to replace the hydraulic pump for the leveling system (wasn't terribly expensive). Vibration is what caused it's failure. So, when the new one was installed, I had the service shop build a brace for it, so, it's better than new.
Our fridge has been running since day one except for when the coach was in service, just like your house fridge. I'm a firm believer of not letting things go unused.
I have an old car that is 50 yrs. old. I have learned over the 15 yrs. that I've owned it to run it regularly, operate the windows (electric), turn on the air, honk the horn.... use every system! It has worked so much better since I started that regimen. I have someone start all my cars weekly when I'm not in residence. It has saved SO many battery replacements.
Can you expound on your statement of 'systems were tired'? What systems were affected?
I can honestly say that I don't think any of our systems are tired.
Safe travels,
MM.
On Edit: Our awning fabric will need replacing in about a year. Not torn but starting to dry out and fading which is normal for 7.5 yrs. It's priced accordingly. I spent $10,000 last year for new AGM batteries and 8 new Michelins.