I seriously don't keep any type of fats/grease from any meats I have cooked. I understand that it's flavourable and all, but health wise, once it has solidified - it's bactrial growth increases, not to mention it's saturated fats. So to answer your question of how long is it good for? - I'd say, the moment you're cooking with it and using it to cook whatever else you may be cooking (eg. potatoes) But once you're done, I wouldn't re-use it.
I have stored chicken grease many many times for soup broth in a plastic tupperware container, usually in the fridge (if hot, on top of the stove until it cools). I've noticed it only lasts a couple of days until it either tastes bitter or molds slightly
I'm not sure I would store chicken grease, I'd get rid of it. Now bacon grease on the other hand should last a long time. That's just my opinion and I have no knowledge to back it up other than it just doesn't seem right to me.