Pap smears were developed to identify problems with the cervix before they develop into cancer. Having them done yearly was based more on "tradition" than on a medical need and several years ago, a panel of nationally and internationally known experts convened to determine how often they need to be done to prevent cervical cancer. These recommendations were confirmed again by the American College of Obstetrics and Gynecology in 2016. It was determined that some women over age 65, without an abnormal pap in the previous 10 years, who do not have compromised immune systems and have no history of cervical cancer or precancerous conditions in the last 20 years, could safely discontinue pap smears.
More recent articles suggest that we may be doing some women a disservice by doing this. Although the rate of cervical cancer is quite low, 19% of new cervical cancer cases are in women over age 65. Based on this, although it is outside of the current guidelines, we recommend erring on the side of caution and doing pap smears every 2-3 years. The American College of Obstetrics and Gynecology supports an annual exam for other screening, such as for other types of cancers, including those of the breast, uterus, vulvar skin, and rectum. Women who may have compromised immune systems, either because of medications that are taken for other conditions or because of chronic illness, should continue with pap smear screening as they may be at greater risk for cervical cancer.
My recommendation to women for any type of cancer screening is that you should stop screening for cancer when you are at a point, either due to age or illness, that you would not do anything if you found out that you had cancer. Until that point, cancer screening may continue to extend your life.