There are two factors that determine the life of a mushroom growing kit. One is how long do the mushrooms take to incubate and fully grow into a harvestable batch. Second is how many cycles of mushrooms can the kit grow. Multiplying these two things will give you the actual life of a growing kit. Even simple growing kits like Back to the Roots will allow you to cultivate mushrooms for two harvest cycles. In the case of a typical mushroom growing kit, you will be able to use it for six months or up to one year.