One of my grandmothers kept the left over bacon on a tray covered with a paper towel in the "saving drawer" in her kitchen. She never put it in the fridge. None of us ever died from eating the left over bacon even days later in BLTs.
However I keep the left over bacon in a zip lock bag in the fridge. I usually use it for another dish later in the day, but it sometimes gets overlooked for several days.
Just be sure to heat it to completely hot!