Using bacon grease--is mine still OK?

Going forward, one tip I learned about when saving bacon drippings is to store it in the fridge in a shallow bowl until it congeals and then scoop out tablespoon size balls. Place the balls on a plate uncovered in the freezer for 30 min or so to flash freeze them and them transfer them to a plastic bag and store in the freezer. That way, when you need bacon fat in a recipe, you have some handy already measured out for you.

Greenstuff, I wasn't aware of the loss of smell--oh, the indignities! Loss of eyesight, hearing, and also smell? Do you know whether or not people's ability to taste tends to diminish as a part of aging, too? When my grandparents were in their late 90s--and even, one of them, her early 100s--it made us sad that all they really wanted to eat in the evening was chicken breast or maybe steamed fish. We would have loved to cook for them, and when we stubbornly did cook, our efforts went mostly uneaten--just a polite spoonful or two.

Greenstuff, I walked into my dad's kitchen and could smell his very long dead sourdough starter at 20 paces - inside a sealed jar inside the refrigerator. We did the same thing: open the fridge and all windows and turn on fans.

Great memories, drkate! I think a whole lot of America used to have that same jar, but I haven't seen one for the longest time. A couple of things to remember--the cleaner the fat, the less likely it will be to go rancid. For the most part, the leftover particles sink to the bottom, so fat keeps them from the air that makes them go bad. But, even though our grandmother's probably didn't bother, straining the fat and refrigerating it will keep it fresher longer. Same with duck fat.

My grandma used to keep a jar on the back of her stove, uncovered, just sitting there. Both her kids grew up and reproduced and repeated the habit of leaving the unrefrigerated grease on the stove and several of their kids have also managed to fulfill their biological imperative, so it's not likely to kill you, especially if your grease has had the advantage of having been in the fridge.
The benefit of leaving the grease on the back of the stove is it's in the line of sight, so you remember to put a splodge in the biscuit dough or the pancake recipe (substitute for butter in biscuits and for oil/melted butter in pancakes), or you can saute the onions for the tomato sauce in it, or use it in the pan you are frying your eggs in, and also you don't have to worry about that refrigerator smell getting in the grease. One benefit of keeping it in the refrigerator is that your non-cook friends won't look at you like you just stepped off the set of The Beverly Hillbillies if they see your bacon jar sitting out. (Your friends who cook will totally get it, and if they are sensible, they will probably have their own jars at home.)
I expect that many people would also argue that refrigeration is just a good idea for anything that can go rancid. In any event, it would probably be a good idea to cover the jar, no matter where you keep it.
If you want to know how to test it for refrigerator smell, here's what I'd do: Put a teaspoon of it in a pan over medium heat it and slowly, so as not to burn the fat, fry an egg in it. You should easily be able to detect any off flavors.

sarabclever definitely does not fall into this category, but I wanted to add one caveat to what boulangere had to say--some people as they get older tend not to smell rancid fat so well. I once walked into my dad's kitchen. A friend, who was getting towards elderly but not even so very old yet, was happily cooking rancid bacon. It was up to me to stop her, dispose of the mess, and open every window that I could.

Third the motion - smell it. Rancid fat of any kind, including nuts, is a smell you'll not soon forget.

I agree with Ophelia. Your main concern is if the oil has gone rancid, which would smell off. It's probably fine.

If it doesn't smell rancid or like your fridge and doesn't contain any moisture it should be fine (sometimes you can get a little mildew from condensation).
I've saved bacon grease in the past by straining the slightly cooled grease through a fine sieve to get out most of the crispy bits and storing it in a canning jar in the fridge after it had cooled the rest of the way. Sometimes I put a circle of parchment paper on the surface to try and limit air contact. Generally I have a plan for it though, so it rarely sticks around more than a couple of weeks. It freezes well if you are so inclined.
The lard I buy at the farmer's market generally keeps for a couple months in the fridge before it starts to smell a little off (off in an old oil, back of the fridge sort of way, not a rot sort of way) and would probably not be harmful to eat, just bad tasting.