John Tuttle writes in 070123 MMDigest

> As an example, I ran a synthetic pouch material through 2-1/2 million
> repetitions to find out if it would fail.  It did not fail.  Five
> years later, in the real world, it was garbage.

John,  Your reference to the "real world" seems to detract from your
premise of "just testing the cloth".  The synthetic material passed
the stress test, but age killed it anyway (and/or light or offgassing,
etc., etc.).

The reverse should also hold true.  The rubber in which you find no
imperfections might develop pin holes after thousands of flexes!

Doing both would seem to allow for a bit more reliability in the test.

Jim McFarland