Many rooms in my place have light switches tied to outlets. Usually just a single switched plug per room. I know where they all are now but it would have been good if there was a little light icon on each plug.

Still, now that I know, I'm not sure I actually want to add that icon, since I know where it is and I'll either plug in a light (in which case I know easily) or I won't (in which case I don't care).