Stockpiling is awesome! But there are some potential problems with it. One big problem is having items in your stockpile expire before you get a chance to use them. Tragic for sure!
How can you avoid this? First of all you need to become intimately familiar with your stockpile. Know its contents inside and out. Check it regularly. Love it. Treat it better than you treat your children.
Second, don't buy more than you can use before the items will expire. But if they are free and you cannot resist, then donate them.
Third, check expiration dates when you buy things. You'd be surprised how a little digging near the back of the shelf at the grocery store can often yield items with much longer expiration dates than the ones in the front.