Now three key groups -- the American College of Obstetricians and Gynecologists , the American Cancer Society, and the U.S. Preventive Services Task Force -- recommend different ages for starting regular mammograms: 40, 45 and 50 respectively. The new ACS guidelines advise that: 
 
 • Women 45-54 with an average risk of breast cancer should get annual mammograms • Women 55 years and up can switch to every other year, but should have the option to stick with annual screens if they choose • Women should have the option to begin annual screening at 40 
 
 The ACS says its guidelines were due for an update—the group’s most recent recommendations date back to 2003, when it recommended annual mammograms beginning at age 40. “The most important thing about our new guidelines is to validate that screening mammography is the most effective thing a woman can do to reduce her chances of dying of breast cancer,” the cancer society’s Dr. Richard Wender told NBC News. This evidence outweighs the occasional study that finds otherwise — such as a large 2014 Canadian study that cast doubt on whether mammograms actually reduce the risk of dying from breast cancer, and a 2012 study published in the New England Journal of Medicine that found that as many as a third of cancers detected through routine mammograms may not be life-threatening. "It's like standard versus HD TV," said Dr. Therese Bevers, the chair of the National Comprehensive Cancer Network's guidelines panel for breast cancer screening and diagnosis, and the medical director of the Cancer Prevention Center at the MD Anderson Cancer Center. "(Insurance) plans will certainly take these updated recommendations into account when evaluating their coverage policies," Clare Krusing, a spokeswoman for America's Health Insurance Plans, wrote to CNN in an email. “It’s easy to say that any test that might result in a prevention of a death should be worthwhile, and why wouldn’t you do that for everyone?” he says. ACS now recommends women at an average risk for breast cancer begin regular mammograms at age 45—it had previously recommended women start at 40—and can transition to every other year at age 55. "Still, some women will choose to begin screening between age 40 and 44, both because they are concerned about their risk of breast cancer, either in general or because they are at higher risk, and are less concerned about the chances of experiencing a false positive findings. “In medicine we are moving closer and closer to bringing about a personalized approach.” 
 
 In a preemptive response to the new guidelines, the American College of Radiology, which represents doctors and groups that perform mammography, and Society of Breast Imaging, a proponent of early detection, said in a statement release to the media that they “continue to recommend that women get yearly mammograms starting at age 40.” 
 
 When asked whether, as a clinician, his own views on screening have changed through the years, Wender said yes. “We both found that the benefit of mammography increases with age, with women in their 50s, 60s, and early 70s benefiting most from regular mammography screening.” 
 
 The new ACS guidelines are more granular than previous ones, with screening advice and frequency broken down by age. “The USPSTF’s draft recommendations and the new ACS guidelines both recognize that a mammogram is a good test, but not a perfect one, and that there are health benefits to beginning mammography screening for women in their 40s.” 
 
 The American College of Obstetricians and Gynecologists is sticking to its guidelines. “ACOG maintains its current advice that women starting at age 40 continue mammography screening every one to two years and recommends a clinical breast exam," the group said. The society says women with a family history or who carry a gene that predisposes them to breast cancer may need to start screening earlier and more frequently.
– For years, guidelines regarding mammograms have been, well, all over the place. The US Preventive Services Task Force recommends women get a mammogram every two years starting at age 50. Since 2003, the American Cancer Society has recommended annual mammograms starting at age 40. The society's first mammogram guideline revisions in more than a decade are only complicating matters. A breakdown, per NBC News and CNN: Women with an average risk of breast cancer should have a mammogram every year from age 45 to 54. If a woman wants one sooner, she should be able to start at age 40, as long as she understands false positives are more common at this age. Women over 55 years can continue annual screenings or choose to have a mammogram every two years since breast cancers develop more slowly in post-menopausal women. This is part of what an ACS doctor calls "a personalized approach," per Time. Keep up with annual or biennial screenings while you remain in good health and have a life expectancy of at least 10 years. Average-risk women can opt out of routine breast checks altogether. Why fewer checks? The society's chief medical officer tells CNN that mammograms aren't always beneficial, and the stress of the procedures, plus misdiagnoses, actually cause harm. If a woman "starts screening at age 40, she increases the risk that she'll need a breast cancer biopsy that turns out with the doctor saying 'You don't have cancer, so sorry we put you through all this,'" he says. Critics, however, say the new guidelines are dangerous since experts only examined whether screening saved a woman's life, rather than led to an early diagnosis. Confused? This won't help: The American College of Radiology and the Society of Breast Imaging "continue to recommend that women get yearly mammograms starting at age 40," according to a release.