Gee, here I sit in my TT constructed 25-years ago this month. Original to the curtains. Zero evidence of exterior leakage. Does it need updating? Sure. Are the other type MY1990 trailers still on the road? Might see them rotting on the side of the the road, but that's about it.
Yes, design, materials and construction matter. And matter most of all. If one wants quality, then be willing to pay for it. Buy used for the best ratio of money spent to value received. A MY2003 TT of this type is not at all "old".
Start with a fresh sheet of paper. Is this RV just a way to escape south to watch TV in a warmer climate? Buy anything you want in that case. The short design life wont shake itself apart with low miles and a few years of post-retirement use seems par before sale.
Still with children at home and looking 25-years ahead? (as did my parents who kept theirs 27-years. One TT and 2 TV). Buy quality at the outset. The long-term cost is far lower as a result.
Good luck
