It's bad for the individual too. Many checks have non-trivial rates of false positives, many treatments have non-trivial rates of severe complication. Checking

It's bad for the individual too. Many checks have non-trivial rates of false positives, many treatments have non-trivial rates of severe complication. Checking occasionally for something specific that's reasonably suspected due to symptoms is good. If you're always checking for everything, you have a high risk of finding something you don't actually have. It turns out that that risk overrides the beneficial chance of finding something real before it has any symptoms.