matociquala and avynrude were visting ashacat and me on Sunday. It being a lovely day, we were enjoying the blue sky and sun out on our deck. Whereupon we learned the answer to this question: What is the safe operating lifetime of a good quality PVC lawn chair?
The answer is twelve years. It is most decidedly not thirteen.
...Two developed spontaneous stress cracks, and Bear's decided that enough was enough and died -- rather explosively.