As for the tensile strength chart, that actually isn't surprising. Even in the Horween video that you can find on Vimeo about shell production, they mention it's tendency to crack when being stretched over the last if the operator running the machinery isn't very careful. However, tensile strength isn't a crucial factor in shoes after they are made. Shoes don't generally wear out and crack because of stretching. They wear out and crack because of dry rot, creasing constantly, abrasion, pollutants that break down the leather structure, etc. Tensile strength aside, shell is more resistant to all of these other types of wear and tear. I'm not old enough to give you a picture of a pair of shell shoes that I can personally guarantee have been worn once a week for 30 years. As jaywhyy says below, Macarthur has shoes that are that old, and he is certainly one of the oldest (if not the oldest) member of SF that I know of, but the size of his rotation is unrealistic for gauging wear. This article (http://howtospendit.ft.com/mens-fashion/6955-plenty-of-horsepower) does mention that there are supposedly more World War I boots that have survived than boots from World War II, the reason being that horsehide was the preferred material during World War I. The author does point out that the source for that statistic is unknown, but it is apparently a recognized fact for what it's worth. Allen Edmonds has said that they receive models in for recrafting that are 30 years old. However, you can't really say how often the shoes are worn. I have no reason to doubt that the leather itself can last that long. I think there is enough reputable information available online to give credibility to that, but as I said in my previous post, just because the leather can last that long doesn't mean that the shoe will.