Radgirl, wise words indeed! She points out "you cannot rely on the individual concerned!....close colleagues almost always notice...but rarely raise concerns out of a misplaced sense of loyalty!"
The nail hit on the head, squarely! Alpha mike echo in post 46 gives a very pertinent example....an aging pilot who went to a different AME for his annual who was shrewd enough to discover it...."the patient was not aware....didn't see the problem....no one had ever pointed it out!"
So there is a problem, as shown in this very thread by the old farts who are going to keep on flying until they themselves make the judgement call! Too often in private aviation, one is rather isolated in one's own private aircraft.
Driving to the airfield in your beamer, gallivanting off to the South of France, how often are your chums (if any!) getting a chance to observe your decline?