You should begin scheduling annual baseline mammograms between ages 35 and 40. If, however, you have a first degree relative (mother or sister) who has been diagnosed with pre-menopausal breast cancer, you should start screenings 10 years prior to the age of that relative's diagnosis. For instance, if your mother was diagnosed with breast cancer at age 45, you should begin screenings at age 35. It is important to remember that mammography is only one part of breast cancer screening, which also includes regular physician check-ups and breast self-examinations.