10. Stay connected. Having regular social contacts with friends and loved ones is key to avoiding depression, which can lead to premature death, something that's particularly prevalent in elderly widows and widowers. Some psychologists even think that one of the biggest benefits elderly folks get from exercise the strong social interactions that come from walking with a buddy or taking a group exercise class. Having a daily connection with a close friend or family member gives older folks the added benefit of having someone watch their back. "They'll tell you if they think your memory is going or if you seem more withdrawn," says Perls, "and they might push you to see a doctor before you recognize that you need to see one yourself."
11. Be conscientious. The strongest personality predictor of a long life is conscientiousness—that is, being prudent, persistent, and well organized, according to The Longevity Project, coauthored by Howard Friedman and Leslie Martin. The book describes a study that followed 1,500 children for eight decades, collecting exhaustive details about their personal histories, health, activities, beliefs, attitudes, and families. The children who were prudent and dependable lived the longest, Friedman says, likely because conscientious types are more inclined to follow doctors' orders, take the right medicines at the right doses, and undergo routine checkups. They're also likelier to report happier marriages and more satisfying work lives than their less conscientious peers.