A long healthy life is no accident. It begins with good genes inherited from your family, but it also depends on good habits. So what's the formula for success? In a recent study, funded in part by the U.S. National Institute on Aging, scientists have focused on groups living in several regions where exceptional longevity is the norm of Sardinia, Italy; Loma Linda, California; and the islands of Okinawa, Japan. Groups living in these three areas of longevity offer three sets of guidelines to follow.