Want new TT trailer but don't want a "Throw Away"

There is no Silver bullet . They will all leak and rot if you let them . Diligent maintenance is the key. Luaun and foam construction is not the greatest,however a 2 year leak will deteriorate all types of construction.
Constant inspection of all seams including,lights,windows,doors etc.
All protrusions to the interior should be carefully inspected at least twice a year.
Longevity is not a factor of cost or even construction, but more a result of care and proactive maintenance.