A random video on YouTube, where the author couldn't remember that the 7th month is July, unlocked a memory of mine: in elementary and middle school, I used to collect physical pocket-sized calendars. I even had two "eternal calendars".
I rarely bought them – most were advertisement handouts, similar to flyers, I guess. Which means that they were almost always for the current year, and actually got used as a calendar.
It all became obsolete when I got a Nokia 6610 with a calendar app.