I wonder how often this is a factor in seam failure? This is why I am extremely hesitant to buy a used tank. The seams may be great sitting in their living room, but moving it through their house, loading it onto a truck, driving twenty miles, unloading it off the truck and moving it into my living room. Will the seals that have already aged still be up to the task after that?
I bought a RedSea 425XL a few months back, drove it 120 miles, should have used more than two people to move it, etc, etc.
we'll see how long it lasts, but its fine.