Water storage.

After inspecting a case of bottled water, I found that three of the bottles had warped our cracked to the point that they were slowly leaking. This water had been sitting unmoved on a shelf for 6 months. Mental note: check your water supply at least once a month. In an emergency situation, that case of water would have yielded only 21 bottles of water instead of what I had assumed to be a good case of water.