Going to the doctor when you're sick is a no-brainer. But going when you're perfectly fine can be a lifesaver. "People who schedule routine visits get the best preventive services, and that sets the stage for success," says Jonathan Temte, M.D., Ph.D., associate professor of family medicine at the University of Wisconsin School of Medicine and Public Health, in Madison. Screening tests are crucial: Your chances of beating virtually any condition are much greater when you catch it in its earliest stages—when it's most treatable or even curable. Use this chart as a guide, but discuss your personal history and specific needs with your doctor.Blood Pressure
When to go: All adults should have their blood pressure checked every two years (every 6-12 months if you have hypertension).
How to prep: Arrive with five minutes to spare and take a few deep breaths while you wait. Stress and anxiety can falsely inflate the results.
What comes next: A healthy pressure is 120/80 or less, 140/90 is considered high, and in between is "prehypertension." Since high blood pressure ups your risk of stroke and heart attack, if you have it your doctor will likely tell you to lose weight, exercise, change your diet, limit alcohol intake, and quit smoking (which all lower blood pressure) before putting you on medication.Colorectal Cancer
When to go: Men and women need an initial screening at age 50 (21 if you have a family history). The gold standard is a colonoscopy every 10 years (more often if at high risk). A flexible sigmoidoscopy is a substitute, but colonoscopy reaches higher in the colon where cancer is more often found in women.
How to prep: For a colonoscopy, maintain a special liquid diet and drink a colon-clearing solution for one to two days. A sigmoidoscopy requires only two enemas the morning of the appointment.
What comes next: If polyps are spotted, they're removed and biopsies are taken of anything abnormal. Questionable spots in sigmoidoscopy are looked at more closely with a colonoscopy.Cholesterol
When to go: An overall lipoprotein profile is recommended at age 20 and every five years after that. Children with a family history of high cholesterol can be tested too.
How to prep: It's a simple blood test, but you need to fast for 10-12 hours before, so make it easier on yourself by scheduling an early morning appointment.
What comes next: Total cholesterol should be less than 200 mg/dL; LDL (bad) less than 100; HDL (good) higher than 40; triglycerides below 150. High total and LDL levels cause buildup on artery walls and block oxygen and blood flow, increasing heart attack risk. Your doctor may suggest changing your diet, increasing activity, and a retest in 3 to 6 months before considering medication.Blood Sugar
When to go: Beginning at age 45 you should be screened every three years—sooner if you're overweight, have a family history of diabetes, or had gestational diabetes.
How to prep: You need to fast for at least eight hours before the blood test.
What comes next: Below 100 mg/dL is ideal, 100-125 is "prediabetes," and 126 or higher indicates diabetes. Losing weight, exercising, and changing your diet is often the first plan of action for lowering high blood glucose and may delay (or eliminate) the need for medication.Bone Density
When to go: Women 65 and older should be tested—earlier if osteoporosis runs in your family, or you have a small frame or have taken steroids.
How to prep: You don't need to prepare for the scans, which are quick and painless.
What comes next: If your numbers reveal low bone density, the next steps are typically blood tests to check calcium and vitamin D levels. Your doctor may also recommend weight-bearing exercises, or calcium supplements or other medications that boost bone density or slow loss.Breast Cancer
When to go: Women in their 20s and 30s need a clinical breast exam at least every three years. A yearly mammogram should be added at age 40. If you're at high risk, talk to your doctor.
How to prep: Avoid deodorant, creams, or powders the day of your mammogram.
What comes next: If the radiologist spots something atypical, follow-up options vary. An ultrasound, diagnostic mammogram (which involves more x-ray images), breast biopsy (typically an outpatient procedure), or MRI may be performed.Cervical Cancer
When to go: Women should have a Pap test every one to two years after the onset of sexual activity, but no later than 21. If you're 30 or older and have had three normal tests in a row, you can get tested every two to three years.
How to prep: Get the Pap when you're not menstruating, and avoid douches, vaginal creams, lubricants, intercourse, and tampons for two days before.
What comes next: If cells look irregular, your follow-up depends on what changes were spotted and the degree of concern. If your changes don't look serious, your doctor may decide to simply repeat the Pap test a few months later (some cellular abnormalities clear up on their own). Or you may get a colposcopy, which uses a magnifying scope to better examine the cervix.