Most of us stock up during the good times and have ammunition lockers or safes as well as gun safes. A lot of the 9mm that I am shooting now cost $4.00 for 50 when purchased. Everyone's needs are different I have heard rules of thumb like 1,000 rounds for each gun. 10,000 rounds for each caliber or gauge. Truth is that you cannot have too much, and ammo will not be in the store when you need it most. Limit to the stockpile is usually the space allowed by the spouse.