A physician who is too thorough in conducting a medical checkup is likely to subject the patient to the discomfort and expense of unnecessary tests.
Conclusion (therefore)
It is generally unwise for patients to have medical checkups when they do not feel ill.
Evidence
A physician who is too thorough in conducting a checkup is likely to subject the patient to discomfort and unnecessary tests.
A physician who is not thorough enough may miss serious problems and give a false sense of security.
It is difficult for physicians to judge how thorough they should be.
Evaluate
This is a Recommendation-type argument. The argument suggests that patients should avoid medical checkups unless they feel ill due to potential risks involved with either extreme of thoroughness from physicians.
The author presents the downside of over-thoroughness: unnecessary discomfort and expense, and the downside of insufficient thoroughness: missing serious problems / false sense of security. Given the difficulty for physicians to judge the right level of thoroughness, the author concludes it's generally unwise for asymptomatic patients to seek checkups.
Goal
We'll look for an answer that amplifies the risks associated with excessive checkups or outright questions the usefulness of checkups when a patient is not ill.