Doctors use the test to diagnosis osteoporosis, which causes bones to become brittle and more likely to break with age.
Now a new study finds women over 65 with normal results may not need to be retested for years.
"They are very unlikely to develop osteoporosis over the next 10 or 15 years and they can be assured that they don't need to have repeat bone testing," said Dr. Stephen Honig of NYU Hospital for Joint Diseases.
A bone density test uses X-rays to measure how much calcium and minerals are in the bone.
The lower the density, the more likely a bone will fracture over time.
Right now there are no formal guidelines for how often a woman should be screened but most insurance companies pay for bone density tests every two years.
Dr. Honig said, "Our practice would be closer to 5 years if someone had a normal bone density test."
Wallach hopes insurance will keep covering regular bone density tests, even if the study shows some women may not need them.
"I don't think preventive medicine is a way to save money," said bone patient Roberta Wallach.
Osteoporosis is the most common bone disease, affecting one out of every five women over 50 in the US.