I have 2 trailers, and 2 quite different experiences.
I think the first seller was pretty honest, with my only reservation about that being the freshwater tank. It had a leak that I found when I filled it later, and he claimed never to have used it because they always camp where there is water. However, when he replumbed the trailer he ran 4' of PEX to connect up to the pump that he wouldn't need to to if he were never going to use that system. I think he really believe that it didn't need new axles, if only because he'd convinced himself of that to avoid buying new axles in the 5 years they had it. (My new axles made a tremendous positive change, btw.) The most frustrating thing he did was to cut the cables from the fuse block to the converter to exactly the length they needed to be, with almost no slack. This made my life difficult when my new converter had the lugs in a different location.
As far as I can tell the seller of the 28' center-bath was 100% honest. When I spoke with him on the phone he almost immediately said "Well, I gotta tell ya, it ain't no creampuff."
He had the trailer a couple of years, but never went very far with it. The only big thing he did was to replace the PPO's garden-hose patches with a well-done red-and-blue PEX installation (he's a master plumber.) My fun with this one seems to all be from the ..um.. "interesting" things the PPO did. I think he was a nutter!
There's a 20-gallon electric residential water heater where the RV water heater and furnace belong. His installation of that shows that he loves loves LOVES screws.
He had some other utility trailer with a 2" ball so he removed the original coupler and put a 2" bulldog on so he wouldn't have to swap out the ball.
He put wheel covers on it that are from an '80s F150, but he didn't bother with valve stem caps.
He put in plug-in 120v lights all over the place, and reiterated his lust for screws by putting in multiple cable hold-downs over the cords, screwed into the otherwise-excellent interior skins. White rivets are winging their way toward me from VTS as I write... (In the process of putting a 120v light in the bathroom he removed the 12v
light fixture entirely, there's another little project...)
He broke one of the window latches (in the rear window in the bedroom) and instead of fixing that, he just siliconed the whole bloody window shut!
He put in a big honking Carrier AC unit that drains on the shell... I guess I'll put up with that until I'm ready to paint, or until it dies from the abuse it's suffered due to the next item.
I'm not sure if something happened to the 30A power cable or if he just couldn't be bothered with adapters. As I found it, the trailer has a short section of extension cord wired directly into the box, just long enough that the male end of the plug hangs down just below the banana wrap, where it is exposed to the elements while you drive down the road. Quality stuff! Marinco inlet and cord are inbound from Amazon.
De-crazy-fying costs add up quickly!