Recommended:
40 to 44 year olds can come in for a mammogram (including sonography) once a year if desired
over 54 years old should come every 1-2 years for mammography (incl. sonography), as long as no other disease causes a limitation of life expectancy to less than 10 years.
For some women at high risk (e.g. genetic, after radiotherapy, etc.), in addition to the Guidelines for the early Detection of Cancer, mammography should be performed every two to three years.