Comment by jancsika

Apparently Petri was driving when he figured out a new fingering for a Chopin Etude he'd use at a concert later that evening[1]. The passenger survived to tell that story, so I think this is more about your correct risk-assessment than physical limitations of the brain. :)

1: Just to unzip: "I don't like this fingering; let me imagine playing with this other fingering; yep, that will feel more comfortable and stronger; I'm now confident enough in the change that I'll do it that way in public, for one of the most difficult piano pieces, without ever having practiced it physically..."