My grandmother used to keep bacon fat in a coffee can by the stove -- as in, never refrigerated. I would not recommend this, but she cooked with it regularly and no one in our family ever got sick from her cooking (which we ate regularly). My kids love bacon, so we cook it weekly, and I keep bacon fat (run from the pan through a fine mesh strainer) in a tupperware in the fridge. I periodically melt it down and give it a stir so that the old and the new are more mixed and it is not just the newest stuff on top that is getting used. I am sure there is a right/safe answer for how long it keeps, but I tend to keep it a really long time, to no observed ill effects. I typically have a cup to a cup-and-a-half on hand at any given time, but usually clean out the container with some massive use and start over at least once a year.
I use it in lieu of oil/butter in most cajun/creole cookery when sauteeing the trinity, add it to bean dishes (red beans, white beans, black beans, black-eyed peas), cook mirepoix for other dishes in it, use it in salad dressings, add a little to frying oil when pan-frying, use it to pan roast potatoes, add to finish green beans, greens and other vegetables, fry eggs in it, etc. There are myriad uses and very few savory things that bacon fat will not enhance. And it does not take a ton to impart a nice flavor.