This dehydrated cayenne pepper is from last year. No preservatives or refrigeration required to keep it.
I also have store-bought pepper. The small jars last me a long time, but the big jar of pepper flakes from my own garden might last all year. That's a good thing, because I don't have any cayenne peppers growing in the garden this year. I do have several other pepper plants growing, though.
It's amazing how much flavor is contained in only a pinch of this stuff! A little bit can liven up bland food, like rice, or potatoes.