It's really simple. A mammogram is where we start. With screening, a mammogram is an X-ray of the breast.
What I and many other experts believe is that screening should start at age 40. Women in their forties should probably have annual mammograms, and then that should continue every two years. If a woman is really healthy and has a good life expectancy in her seventies, then that should continue, probably, to 80.
The biopsies...those kinds of things only come into play if there are abnormalities or suspicions of cancer noted on the mammogram.