Every fourth year, someone is elected President of the United States. Every fourth year, since 1896 save during times of war, the world has celebrated an Olympiad. And, every fourth year, the month of February is one day longer, reminding us that every fourth year is a Leap Year — usually.
Leap Year is a necessity. The earth we live on revolves around the sun in about 365.242189 days — or, to be precise, a total of 365 days, 5 hours, 48 minutes and 45 seconds.