Keeping Buttermilk & Heavy Cream On-Hand

I have quite a few recipes that call for buttermilk, but who uses it often enough to always have it on-hand in the fridge?  Also, what about half & half, heavy cream or whipping cream?  These are always things I need, but I usually have to run out and buy them if a recipe calls for them.  After I started making my Oatmeal Buttermilk Pancakes regularly, I wanted to find a way to keep these items on hand, so I tried freezing them.  It worked beautifully.  I now purchase those little pint cartons of all these things and keep about 3-5 of each in my freezer.  I just defrost them in the microwave and add them to whatever I'm making.  It works great!  I'm sure they'd last in there a couple of month just fine, but I use mine up before then anyway!