Breast cancer screening is best done at home, before age fifty. A monthly check will show you any changes to your breasts, for which you should make an appointment with your doctor to schedule a breast exam, and if needed, a mammogram. From age 50 to 74, an annual screening is recommended. From age 74 and up, it is a choice between you and your doctor as to whether or not you wish to continue screening for breast cancer.
Each of the recommendations from the different institutions are listed cdc.gov’s guidelines on breast cancer screening.