Early retirement has always been a bit confusing, define early. I retired at 24(yes twenty four) after being a commodities broker for 3 years. Went to med school, retired from specialty A, after a while, reentered in specialty B. Now practicing roughly 12-18 hours week, yeah I know 3-4 hour days are intoxicating. It allows for constant learning, interaction with people, and a bit of extra cash for excursions around the nation and the EU. The diet/exercise advice noted in the article posted,I have practiced for the past few years, as most physicians are somewhat ignorant of proper health habits and nutrition.