Our house was, I think, originally a single-family house, built in 1910, and split into three apartments in the 1940s. I am guessing that the owner lived upstairs because that was the larger and much nicer apartment, so when we got rid of the extra kitchens and one of the bathrooms, we kept the ones upstairs, so our kitchen and bedroom are upstairs, with a smaller bedroom downstairs, and we turned another into a walk-in closet and took a wall down between two others to form a large library.
I give you all of this as a way of illustrating why we tend to go up and down the stairs often throughout the day. Until the past couple of years, I would run up and down the stairs more often than I would walk. But after a few falls (not all the way down the 15 stairs) and some stumbles, I am more careful going down the stairs now, but it's less painful running (not fast) rather than walking upstairs, since my knees hurt more when I ascend the stairs slowly.
I give you all of this as a way of illustrating why we tend to go up and down the stairs often throughout the day. Until the past couple of years, I would run up and down the stairs more often than I would walk. But after a few falls (not all the way down the 15 stairs) and some stumbles, I am more careful going down the stairs now, but it's less painful running (not fast) rather than walking upstairs, since my knees hurt more when I ascend the stairs slowly.