I have owned this mechanical pencil since college. I was in class one day and I wondered to myself (sometimes my mind wanders in classes) if I could use the same pencil for a whole school year (I also think of weird challenges sometimes). That was my senior year. I surpassed my goal and used it for both my senior year and grad school the following year.
I also use it to plan my lessons when I teach. It usually permanently resides in my backpack, but I lent my backpack out this winter and I haven't put it back yet. I have been nostalgically using it in the meantime.