My latest home improvement project is changing out all the old style electrical toggle switches and putting in the more modern flat ones. All told there are 24 switches and switch plates in this plastic bag that is sitting on a shelf in the work shop area of the garage. Eighteen are single pole and 6 are of the 3-way variety.
Two of those 3-way switches, one upstairs by the front door and another downstairs in the garage, are a total mystery because they controlled nothing at all as far as we can tell. I hate to tell you just how many trips to Home Depot it took to complete this project, it seemed like a half dozen, but was probably less. The first time we went we bought a 10 pack of the flat switches, four 3-way switches (2 each for the garage light and the downstairs hallway and several varieties of switch plates. Of course I had miscounted (in my head) how many switches I needed. Not only was I unable to count straight, I was surprised by the mystery 3-way switch in the set of four by the front door.
Even with the help of my lovely bride and a tour of the house, when we got back from a second trip to HD we still missed a couple places that needed switches. Then after installing a remote controlled ceiling fan I needed a blanking plate because I removed the light switch entirely. This necessitated another trip to the big box home store. There may have been another trip in there somewhere too, I’m not sure So when I was surprised by the second mystery 3-way switch in the garage, that did nothing, I just put a single pole switch in its place (taping off the extra wire.)