For women to actually prevent breast cancer, the first thermogram (NOT mammogram) should IMO be done around age 25. This is because breast cancer takes up to 15 years to become serious and the highest fatalities occur between the ages of 40-44.
By the time a tumor becomes the size of a pin head, which is nearly two years into its growth, it can no longer be sustained by the normal blood supply and so it develops its own. The development of that blood supply is called angiogenesis.
Thermography is the ONLY technology available that can detect angiogenesis. It is widely used in Europe. A tumor at that early stage cannot be detected by mammography or any other technology.
Also, each series of mammograms increases a woman's risk of developing breast cancer by one percent per breast. As the effects of radiation accumulate over time, if one was to follow the American Cancer Society's recommendation to have mammography every year from age 40 to 50, that risk for developing breast cancer has increased 10 percent per breast over and above whatever ones risk was already.
The other alternative is to have digital breast tomosynthesis. It overcomes the limitations of conventional mammography. The big problem in conventional mammography is that 3D anatomical information is projected into a 2D image plane, limiting the ability to detect certain cancers.
And dense breast tissue and overlapping structures often lead to false positive or false negative results.
Digital tomosynthesis are found to have an average lifetime risk of fatal breast cancer of 1.3 cases, per 100,000 women 40 years of age at exposure. On the other hand, mammography, either digital or screen-film, performed annually in women from age 40 to age 80, is associated with causing fatal breast cancer in 20 to 25 cases out of 100,000 women
My advice is to have thermograms done starting at age 25, if suspicious, then breast ultrasound or MRI, if suspicious, then breast tomosynthesis.