Screening (American Cancer Society): Average Risk: 40 - 44 years old: have the option to start screening with a mammogram every year. 45 - 54 years old: should get mammograms every year. 55 and older: Can switch to a mammogram every other year, or they can choose to continue yearly mammograms. Screening should continue as long as a woman is in good health and is expected to live at least 10 more years. High Risk: Definition: Women with lifetime risk of breast cancer of 20% or