I noticed my heel was occasionally getting hung up under the first stair (see the bottom picture below) and I don't like the idea of falling headfirst down our basement stairs. My fix was to cut a piece of 1-inch square wood diagonally using my table saw and then screw it in, making it much less likely I can catch my shoe under it. The hard part of this was getting the screws to go straight up with almost no room to work. That was solved using a right-angle angle driver, available at the link below. Safety first!