I had to pay a visit to Time and Date to get to know Why Leap Years Are Used.
Amongst the few things I gleaned was that after 2008, to see the next occurence of a Leap Year with 5 Fridays we will have to wait until 2036.
Looking way past our lifetime, the current system for most of us, they state that "the Gregorian calendar has a 400-year cycle until it repeats the same weekdays for every year–February 29, 2008, is a Friday and February 29, 2408, is a Friday".
There is much more to learn from their Leap Year page but I will let you explore the rest.
Do check their Trivia Page on February 29 which combines stories and history.
From their Brief History of Leap Day, I discovered that "In ancient Rome, Leap Day was on February 24 due to February being the last month of the calendar. The original Roman calendar added an extra month every few years to maintain the correct seasonal changes".
A trip down history lane