I have a lifetime supply of old Mercury index nocks, the good ones, in white and yellow for my wood arrows. I've had a couple of white ones break when shot, but they were old and had discolored. I think sunlight coming through the window deteriorated them, but yellow nocked arrows stored in the same place have never failed. My bows have not been damaged, fortunately. I renocked the arrows with discolored nocks with more from the same batch that had been stored in a cabinet, and they're fine.