OVER THE YEARS the annual medical examination had become something of a sacred duty. Throughout that time, however, a minority medical opinion held that, for people under 40 who had no alarming symptoms, annual checkups were a waste of time and money. As health costs skyrocketed and it became more and more important that money and medical resources not be wasted, that minority view gradually emerged as the majority opinion. Now the American Cancer Society -- in a dramatic change of its earlier position -- has added its voice to the newly dominant view.

The Cancer Society's new guildlines call for cancer checkups only every third year for those under 40, and they substantially reduce the recommended frequency for many common cancer tests, such as Pap smears and mammograms. The changes reflect new answers to several questions. First, which tests at what frequency are medically effective? In other words, to what extent do the tests reduce the mortality or severity of different kinds of cancers? Recent research has indicated that for many types of cancers -- because they grow very slowly, or because they are very difficult to detect at an early stage, or for other reasons -- frequent tests do not yield a significant medical benefit. Second, the Cancer Society considered the justification of the risks involved. Though a test -- for instance, an X-ray -- may involve only a small risk, the risk of harm from that test may be greater for many people than the risk of contracting cancer. Finally, the new guidelines depend on new assessments of whether the costs are reasonable in relation to the resulting medical benefit.

This concern with costs and with the wise allocation of limited medical resources is part of a growing -- and very welcome -- trend. Just a few weeks ago one of the country's leading hospitals announced that it would not longer perform heart transplants because of the enormous cost in medical resources being expended for questionable, small health benefit. The country does not -- and never will -- have unlimited doctors or dollars: it is in everyone's interest that those available be used as effectively as possible.

The new guidelines also emphasize that people are not all the same. Especially for cancer, different patients incur very different risks, depending on family history, smoking habits, obesity, age and so forth. The old dependence on annual checkups was a waste of time for some and gave a false sense of well-being to others. The new policy correctly urges each individual to tailor medical visits to his or her own particular situation and to be alert and responsive to symptoms as they appear. It emphatically does not mean that symptoms should be ignored just because they appear between recommended medical visits.