The very first factor why calendars are crucial is to arrange your days, months, years, and also seasons. Utilizing a calendar to do this is really easy.
The 2nd reason coincides as the very first one, yet it is much more challenging and requires some estimations. This is the solar year calendar. The solar year is a human innovation. The solar year refers to the Julian calendar as well as is used to figure out the Gregorian calendar. Both calendars are almost the exact same besides the leap year, which is twice a year in the Gregorian calendar.
Source image: blankcalendarpages.com