Recently my neighbor borrowed my baking soda so I bought a new box. One good thing I found was that it now comes in smaller boxes. How often do you buy it? Me...maybe 2 or 3 times in a lifetime??? Anyway, I asked a woman who was at the same spot in the grocery store as I was "do you periodically buy new bkg soda and other spices, or wait till you run out? She said she never buys new unless she is out of it. But, she did google it and found out the shelf life is a very long time. My question is: do you periodically replace your spices or just buy it when you run out? I'm not seeing any expiration date on them.