Deciding when to get a routine mammogram is confusing. Guidelines disagree on whether to begin at age 40, 45 or 50, and whether a yearly or every-other-year scan is best. New research aims to one day help tailor advice by using genetics and other factors to determine whether a woman's risk of breast cancer is low, high or somewhere in between. For now, experts say talk with your doctor about factors such as cancer in the family and your own health history to decide when to start screening — and then stick with it.