I only get a flat once a year or less. Perhaps the slime was old or something by the time I got my first puncture. The first thing it hit was a tiny bit of wire, and it didn't stop that. The next, probably 6 months later, was a T50 staple, one of the ones from a common staple gun, two very small punctures. It didn't stop that either. Then a year or so later, a tiny sliver of glass. Didn't help. Of course, by then all the slime had been blown out of the tube all over my fenders, so I didn't expect it to help.