Michael Jordan
After all was said and done, Michael Jordan, arguably the greatest basketball player of all time, had played in the NBA for fifteen seasons and ended his career at the ripe old age of 40. So why is he on this list? Well, Jordan retired early not once, but twice, before his third retirement finally stuck. His first retirement came in 1993 at age 30, after leading the Chicago Bulls to three straight NBA championships. When his foray into professional baseball was unsuccessful, Jordan returned to the Bulls for another three championship seasons before retiring a second time in 1999, becoming a part owner of the Washington Wizards, and returning in 2001 to play for the Wizards for two years. Whew!