Leap years are for people who can’t plan ahead

Egyptian calendar, dating system established several thousand years before the common era

[It] consisted of 365 days organized into 12 months of 30 days each [..] There was apparently no attempt to introduce a leap-year day to compensate for the slippage of one day every four years; as a result, the civil calendar slowly rotated through the seasons, making a complete cycle through the solar calendar after 1,460 years.
The Egyptian civil calendar was altered by Julius Caesar about 46 BCE with the addition of a leap-year day occurring once every four years.

Egyptian calendar, Encyclopædia Britannica