We just came through the backside of Irma, live in north-central Florida. We lost power for three days and had to dig out the hurricane kit. I had a commercial pack of batteries that were stored since 2001 from my days as a bomb technician. They were date coded to use by March 2003. They were alkaline D cells from a popular company that has a copper colored ring around the top. I put them in a 2 cell mag-lite that ran for 7 continuous hours. That's not a typo, seven hours. The flashlight was hot as a firecracker but keep going. I was absolutely stunned. The entire kit was always in a climate controlled environment not subject to moisture or temp changes. Sixteen years is impressive to me.