Wow, something weird is going on in your house. I literally never change my light bulbs, I was just thinking about this the other day when I was looking at my extra bulbs and considering where to store them. It occurred to me it's been literally years since I changed a bulb, whereas in the old days it used to be a regular occurrence.

Also it's not hard to work out how much electricity you are saving. If you are worried about a couple of bucks, it won't take much usage of a 80W bulb to blow through that.