Assurance from the doctor // Assurance from the  doctor - © Jose Luis Pelaez Inc|Getty Images (Assurance from the doctor - © Jose Luis Pelaez Inc|Getty Images)

You're busy. So busy that you might not even make it to the doctor when you're sick, let alone for routine physicals, right? Well, here's the good news: While you do need some basic checkups, they're fewer in number than you might think—just a few per decade. "With these screenings, you'll catch things early, before you have symptoms and when they're most easily treated," says Christine Laine, MD, editor of Annals of Internal Medicine. Beyond an annual gynecological exam (a must for every woman), these are the bare minimum—but most critical—checks you'll need for the next, oh, 10 to 50 years!

Your 20s

Complete physical. Go in for your first at age 21, then every five years until age 40, when you should start getting one annually, according to Marianne J. Legato, MD, professor of clinical medicine at Columbia University College of Physicians and Surgeons. Dr. Legato recommends getting checks of your blood sugar, cholesterol, thyroid function, liver and kidney function, and vitamin B12 and vitamin D levels. That's because many serious health threats, such as high cholesterol, are silent killers with few to no symptoms to sound a warning. "I don't know how many times I've seen a trace of protein in the urine of a 25-year-old, which could mean loss of kidney function later," Dr. Legato says.

Pap test. The Pap can spot the earliest signs of cervical cancer, when the chance of curing this disease is very high. It's especially vital to be tested when you're in your 20s because you're more likely to have multiple sex partners and be exposed to the human papillomavirus (HPV), which can trigger dangerous cell changes. Get it at your yearly gyno exam, starting at age 21 (if you haven't been tested before then). At age 30, if you've had three consecutive normal results, you may only need a Pap every three years until age 65.

Tests for sexually transmitted diseases (STDs). There are some 19 million new STD infections each year, almost half of them among 15- to 24-year-olds. "Often there are no symptoms," says Beth Jordan, MD, medical director of the Association of Reproductive Health Professionals. "If left untreated, some infections can lead to infertility and other complications." Get tested annually for HIV, chlamydia, and gonorrhea when you become sexually active (and when you're starting a new relationship) until age 24, or until you're no longer "high risk" (meaning you have multiple sexual partners ora partner who has multiple partners, or you have unprotected sex). Ask your doctor whether you should be tested for the herpes simplex virus.

Skin check. Melanoma, the deadliest form of skin cancer, is the leading cause of cancer death for women ages 25 to 29. What's more, incidence among young women has risen by 50% over the last three decades, largely due to the use of tanning beds. See a dermatologist annually if you have a family history of skin cancer or semiannually if you have actually had the disease. The rest of us can do a yearly self-check.

Go the extra mile:

  • Get your blood pressure checked every two years. Some young adults do develop high blood pressure, which can up your risk for heart disease—the leading cause of death for American women.
  • Have your cholesterol tested every five years starting at age 20 if you smoke, are obese, have diabetes or high blood pressure, or have a history of heart disease or a family history of heart attack.
  • Go for an eye exam every 5 to 10 years beginning at age 20, especially if you already wear glasses or contacts. An eye exam can also flag other diseases like diabetes.
  • Get to know your breasts and all their natural lumps and bumps so you'll be better able to tell if something feels suspicious later on.

Your 30s

HPV test. HPV is the leading cause of cervical cancer, and most sexually active women get the infection at some point. While 90% of those infections clear up on their own, that's less the case as we age. "Beginning around age 30, women become more prone to persistent infection because our immune systems are less robust," says Debbie Saslow, PhD, director of breast and gynecological cancers for the American Cancer Society. So get the HPV test at age 30 and then with your Pap every three years if results have been normal.

Blood sugar test. "Here, we're actively looking for blood sugar that's heading toward abnormal—anything above 90 milligrams per deciliter—so we can intervene before you develop full-blown diabetes," says Pamela W. Smith, MD, a specialist in metabolic medicine at the University of South Florida College of Medicine. Go in for the test at age 30, and then every three years until you turn 50, when you should start getting it annually (since the risk of diabetes increases significantly with age).

Don't forget! An annual gyno exam with breast and blood pressure check; a Pap test every 3 years after normal results; a physical every 5 years; an exam every 5 to 10 years; a skin self-check annually; a cholesterol check every 5 years if you’re high risk.