I've learned a great new tip...so I want to share it with you! I used to be one of those people who had milk spoil before it all got used up. Not anymore! Or at least not very often. :-)
Now, when I open a new gallon of milk, I pour it into glass jars, label them, and stick them in my freezer. Just be sure to leave enough headroom in the jar for the milk to swell as it freezes! Otherwise it may crack the jar. I usually label the lid with a piece of masking tape with the date written on it. That way I know which ones to use up first. Also, note that the milk will look yellowish after it has frozen. But don't worry, when it thaws, it will be white again and smell fresh as new!
This tip has saved me lots of money, plus now I don't have to worry about running out of milk!