A full year consists of 365 days and 6 hours.
Every four years the Gregorian calendar gains an entire day (6 hrs. x 4 years = 24 hrs).
Every four years we synchronize our calendar by adding an extra day in February.
Adding that extra day gives us leap year.
Those born on a February 29 date are called leaplings.
If you were born -- say in 1980 -- theoretically you have only celebrated 4 birthdays, you are only seven years old, you appear on planet earth only 25 times a century, and in order to join the elite and exclusive Leapling Octogenarian Club you will have to live among us non-Leaplings for 4-hundred years!