I broke one of mine in 2003 by dropping a 4x4 post on it, and it shattered into 1,173 (or thereabouts) pieces, but held together on the panel. It's still running to this day, putting out 96% Voc, 77% Isc, and 76% of the working current, all compared to the other identical unbroken panels. Since the system is still adequate for my purposes, I never bothered to fix it, and I'm quite happy with the apparent robustness of solar electricity.