Okay, I'll admit I'm highly anal retentive! As long as the stuff isn't burned, I will strain it (If necessary) and put it away in the fridge. I now have jars of:
- beef fat
- chicken fat
- lamb fat
- duck fat
- bacon grease
in addition to lard, clarified butter, and leftover oil from frying chicken.
Mostly, I move them around the fridge.

Sometimes I open them to see if they've gone moldy yet -- then, sigh, I dump them.
No, seriously, I might add a bit to the canola or olive oil, or use some on its own, to enhance the flavor of a side dish (like using a little lamb fat in the lentil pilaf to go with lamb chops, or chicken fat in the rice with a chicken dish). When I want to be really decadent, I'll use the duck fat to saute potatoes. Of course, bacon fat when I cook collards and such. And whenever I make "pastitsio" or "moussaka" I use beef fat to make the bechamel -- I just like the way it tastes.
As a flavor enhancer, I'd rather use a little fat than MSG anyday!
P.S.: Chloe:
Never dump the grease down the drain!! It can clog and make your life miserable. Put it in a container in the trash.
A hint: I chill or freeze it first, then put the block of fat into the trash can -- less likely to run all over that way.