I generally put pies in the fridge because they last longer. If I planned on them being finished within a day or 2 I would feel ok leaving it out. I think the internet would tell you to put it in the fridge though.
I tend to cook with olive oil or butter but if I am just greasing the pan after washing I will use bacon fat. I pour off the grease after cooking bacon and save it in a container by the stove.