"Patients really should be empowered," says Dr. David Katz, director of the Prevention Research Center at Yale University School of Medicine. "You shouldn't assume that your doctor knows everything he or she should know." So preserving your good health means educating yourself. The U.S. Preventive Services Task Force maintains comprehensive guides to the latest recommendations for disease prevention, which include blood-pressure screenings for all adults over 18, cervical-cancer screenings for all sexually active women, and counseling to help you quit smoking and keep a healthy weight and consume alcohol moderately, among other good habits.