Of my 3 pack of dual chambered ones, I used one for over a year on many trips with no problems at all. I gave one away, and it is still in use. The last one I used recently and it leaked down right "out of the box". I would say that if one holds up for the first night, it should be good for a long time.
All in all, one of my best gear purchases!
Want to sell any of those?
I have almost purchased a 50ct box, but thought better of it (for a change). I am in dire need, and have given up hope that BPL will restock. Are yours the duals?
Edit: PM sent