Just used the first battery and it works fine. Light is as bright as new.
I use the led lights on my dogs leashes at night. I feel safer knowing others can see us in the dark.
I buy both the 2016 and 2032 batteries for my various night lights, and I find always that Nite Ize ships promptly, and that the batteries are of very high quality, and very fairly priced. I am a satisfied repeat customer! Short of the development of some sort of permanent or rechargeable battery, I believe the Nite Ize Nite Cells are the best product of their kind.