I suspect getting older might have something to do with the deepening fear/caution when around high places--I know it has for me. Places that never used to bother me now sometimes make me feel pretty tense, and when my wife (who is somewhat younger than me) stands on the edge of a drop, where only a decade ago I used to stand myself, I have to struggle with the urge to pull her back.
Also, seeing and/or knowing someone who has died or been seriously injured in a trail fall or making a commonplace steep scramble starts one to thinking a bit differently, too, I think. I realize now, how just a little more caution could have made a big difference.
Nowadays, when I come to a sketchy place and I'm feeling a little on edge (psychologically) I allow myself to stop, take a break and think it through. After a taking a moment to analyze my fear within the context of the actual risk, I usually get things back into proportion. And that usually means moving ahead. I guess the fear is just my brain's way of reminding me not to forget to use it. In any case, the last thing I want is to be part way up, down, or across and then lose my nerve.