We had an old TT that just sat in seasonal site before we picked it up dirt cheap, served us well for several years. It had had some water leaking around a window that was repaired at some point, but no real damage to the outside or any delamination.
After having it for several years we rescued a GSD who runs and kicks in his sleep. We found out the damage was to the inside wall, it was very soft and the dog kept kicking big holes in it. A little while later later the header over the slide started sagging from rot.
So I'm a bit OCD about water leaks in the new one. constantly checking everything.