When should you get a mammogram? Conflicting advice makes it hard to know

The American College of Radiology and other health groups have differing recommendations on when women should start getting routine mammograms, ranging from age 40 to 50, and whether they should be done yearly or every other year. The conflicting advice is partly due to guidelines being designed for women at average risk with no cancer symptoms. Breast cancer is a common disease, making it hard to determine who is at average risk.