Putting something in the advertising like: "new tires, brakes and bearings in 2020." Do you think buyers of used trailers would see how enhancing that is?
-Speak
Probably works for most prospective rv trailer buyers.
Generally I shy away from a used anything that the owner/dealer say he/she rebuilt. Regardless who said what on the subject the first thing I always do before putting a new or used trailer on the road is R/R behind the hubs.
Trailer brakes are simple to work on however after putting several new and used trailers in service when I hauled... many times I've found something even they forgot to install or install correctly.