Basically it all depends on the original construction of the trailer to determine if it will still be a quality trailer used. For example a dump trailer is probably pretty safe bet it still has a lot of life in it (depending on age and use of course). Smaller hauling trailers are more likely
to have lower quality construction, so take the time to really inspect.
The fact that you can typically get a used trailer for about half the cost of new makes it worth the time to find the right one. A few things to inspect when buying a used trailer:
Check the trailer floor for stability and make sure it is not rotting or rusting
Check tires for wear, uneven wear, dry rot, or bulges
Check the hitch, making sure that it latches and unlatches properly
Then of course all the usual stuff, how old is it and what has it been used for to get a feel for how the trailer has been treated. A new trailer will be shiny and clean, you will know it’s background of course because you are the first owner. Buying a new trailer does not guarantee you won’t have any problems, but it does lessen the risk. With due diligence and a great selection of used trailers to go through you will no doubt find a much better deal buying used over new.

