As even casual observation reveals, those who live to be ninety or older have, typically, not spent much time in the company of doctors and high - technology medicine. (firstthings.com)
This latter part seems to be what others have referred to via casual observation. (davidmarkbrownwrites.com)
Sometimes it is a studio visit and a visitor's casual observation about a painting that opens up my mind to see it differently. (paintingperceptions.com)