I is fine to do a pre-purchase inspection, but many of the issue happen over time. My TT is 10 years old. I have towed over 40,000 miles. A few of the problems encountered include,
+ The screws holding the bottom of the front wall to the floor rusted out and broke free. The front wall separated from the floor.
+ The screws holding the bed to the front wall were unsupported across a 1/2 inch gap as the front wall moved.
+ The pantry shelves collapsed because the wood framing split at the screw holes.
+ Numerous other loose screws and trim typical from heavy use.
My point is many of the thing are occur over time. You cannot see these issues when you buy, so it pays to be handy with tools.