Stockpiling is when you buy items you need when they are at their rock bottom price when they go on sale, and combining that with a great coupon. Your stockpile grows when you are grabbing more than one of these. A stockpile can be as little as having 4 of something, or as big as 20 of something (depending on your needs for that item). Stockpiling essentially saves you money in the long run, and overall in general when shopping.
Important things to keep in perspective with it all:
Saving Money: If you are spending money ordering coupons and getting every deal possible, are you really saving your family money in the long run??
Saving Time: If you are busy finding deals, coupons, stock of items in the store, is it all worth it spending all that time?? TIME IS MONEY!
Family Time: Remember, couponing/deals are here for us to save our families money so we can spend extra time not working as hard and spend that time with them!
Above all you have to Find That Balance that works for YOU!
Everyone is different: Use different products, have different coupons available, different size families, etc.