Doctors are, in my experience, very good at justifying preventative checks they thought of and very poor at justifying ones you thought of. In both cases, they

Doctors are, in my experience, very good at justifying preventative checks they thought of and very poor at justifying ones you thought of. In both cases, they're correct - since no intervention is risk free, even if you have a 0% false positive rate in the sense of "I found a mass in your arm", for example, you might still have a worse outcome rate if the rate of "mass in your arm causes harm" is lower than "complications from removing mass in your arm". That's not to say that their suggestions are right and yours are wrong, just that they're right about the reasoning but tend to dismiss concerns that they didn't think of and justify ones they did, and we need a more complicated basis for justifying this than "I think".