Well I'm just a lucky, lucky man today.... I discovered not ONE, but TWO ROLLS of Theraband Gold at work today! Virtually untouched! It's too thick for us to use with patients who come to us for physical therapy. So I asked the boss if I could have the box. (I didn't tell her that I wanted it to make slingshots with...I'm not THAT stupid!) But...while it LOOKS good, I was wondering if anyone knew what the "shelf life" of this stuff is? I'm sure we've had it for YEARS, because even though it's been in a controlled environment (not exposed to sunlight or extreme temp changes), the box is actually yellow with age. Anyone know?