lol depnds what we have to cerial, and what people feel like eating we never throw away milk, bad or not, when it goes bad, we make finnish pancakes(the more sour the milk, the better the pancakes taste! I know it sounds gross, but not a single person who has tried them does not love them ) nobody in my house drinks milk alone, we buy both skim, and 2%, mostly we use milk in cerial, and I will drink it with chocolate cookies, otherwise I find milk to be gross lol so lets see about 6 liters will last us all about 2-3 weeks, 6 because my mom buys a 2 liter carton for me, and a 4 liter jug for herself and my brother.