Get a mammogram, a blood pressure reading, an HIV test. The list of recommended health screenings can seem endless. How do you know what you need and what’s worth the cost and time? The short answer is talk to your doctor, says Sara Doss, MD, a primary care physician and assistant professor of medicine at Loyola University in Chicago.

“In general, everyone older than 20 should get cholesterol, high blood pressure and diabetes screenings,” Doss says. “And for detailed guidelines about key screenings, check out reputable health information sources, such as the U.S. Preventive Services Task Force or the Centers for Disease Control and Prevention.”

Also, keep in mind that although screenings aren’t perfect and some people may need more tests, that’s not an excuse to avoid the doctor’s office. Why? Because that’s when your health may really suffer.