Thanks Bjorn.
I try to keep away from the really stressed out bows, and never had the glory of shooting one that blew up.
The 5 line rule sounds pretty fair. I have shot single-lined stressed bows, with the stress near the riser, and they seem pretty sound.
I always wondered about the dry fires, loose nocks, or lightweight arrows causing the stress versus heavy use. I think this keeps me shooting heavy arrows from a variety of bows instead of just overflexing one.