Most interesting, when you analyse the idea of the “routine check up” and the 'get it early' belief, is the cultural aspects...some cultures have a more fatalistic approach to disease whilst others have an almost obcessive compulsive attitude towards health isssues like screening. 
 
This creates an interesting situation in many nations where the dominant culture's values are expressed in health policy and then the policy makers wonder why the other cultures don't engage. Screening highlights this: the dominant culture usually emphasises population screening programs, the minority cultures might well say what is the point, it only does a lot of damage with a very low chance of benefit so why bother? Another feeling is that we (disadvantaged minority) don't live as long anyway (usually very true) so why bother? 
 
There is no right or wrong in this when it comes to things like prostate and breast cancer (assuming that readers have been keeping up to play with some of the latest research on breast screening) yet we have these public messages suggesting that it is irresponsible not to screen.  
 
The inequalities in screening are very high.  Even fully publically funded screening has a great difficulty overcoming the deep seated factors leading to inequity (let us not talk of the inequity of privately funded or insurance/risk funded screening).  If you step up to a higher level, screening, be it in a program or outside (opportunistic), can make a significant demand upon diagnostic and theraputic services, which in any nation with a limited health resource means someone (usually at the bottom) will dip out when it comes to access to these services for symptomatic disease reasons. 
 
I wonder if any nation anywhere, when deciding to initiate a screening progam, has really considered the inequities impact?

Central to our belief in the “check up” is the idea that early detection must be good. The strength of construct validity of this idea has overwhelmed evidence to the contrary.

Perhaps science fiction is to blame: Doc McCoy’s pocket scanner certainly reflected that widespread belief that only if we could see inside the human body then we could pick up diseases early enough to “nip them in the bud”.

Maybe its deeper in our psyche.  The early bird gets the first worm. Nip it in the bud. 

Different cultures have the same concept. In this country, Maori (indigenous Polynesians) have a proverb which says “The first come to eat food, those who are behind swallow spittle.”

The problem is that the research on the routine medical check up usually does not focus on true outcomes, because it is too remote from this although for specific realms of medicine there are intermediate benefits e.g. cardiovascular and diabetes. However as for listening to the health y heart, palpating the asymptomatic abdomen, or inspection of the unsymptomatic urine, then the data is either lacking or unsupporting.

Microscopic haematuria is a classic. No use as a screening tool in fact probably downright dangerous for the high probability of a positive result is matched only by the high probability of an unhelpful or incurable finding following invasive investigation. And as for prostate screening, well the Americans found it didn’t save lives and the Europeans found it did but at a very significant cost in terms of adverse patient outcomes.

But we still do it and the tea leaves suggest this will not change.

That’s medicine.