The general issue is that doing more tests can catch more things earlier. But all tests have false positives, and false positives can lead to more tests and in some cases to unneeded treatment, which can cause more harm than good.
It's perhaps unintuitive, but more testing isn't always good. The benefits need to outweigh the risks, and it isn't always the case. There are ongoing debates about who should be screened for various types of cancer, for example, and the "right" answer changes over time - as we find ways to reduce false positives, as we find better treatments, as we better understand the diseases, etc.
It's tempting to do more tests because it feels like you're doing something. You don't want to get sick later and feel like you could have prevented that. But that's an irrational form of thinking. All that we can do is make the best choice now, given our current information. As GP's links mention, the best choice we have now often seems like "avoid tests that aren't clearly needed."
It's perhaps unintuitive, but more testing isn't always good. The benefits need to outweigh the risks, and it isn't always the case. There are ongoing debates about who should be screened for various types of cancer, for example, and the "right" answer changes over time - as we find ways to reduce false positives, as we find better treatments, as we better understand the diseases, etc.
It's tempting to do more tests because it feels like you're doing something. You don't want to get sick later and feel like you could have prevented that. But that's an irrational form of thinking. All that we can do is make the best choice now, given our current information. As GP's links mention, the best choice we have now often seems like "avoid tests that aren't clearly needed."