Minor trim adjusts ( a click or two) is fine on each flight due to many different factor, usually climate related.

Major trim adjustments for each flight = Bad = Something is wrong.

As far as nyrods are concerned, it usually takes a pretty wide difference in temp/humidity change to see it. I replace nyrods with either golden rods or my favorite, carbon fiber, for the strength. SIG uses nyrods for a lot of their models. I own 2 SSE's and I defintely saw a difference in high stress maneuvers, mainly knife edge and lomcevaks between the nyrods and the CF rods. Nyrods do flex a little more and it seems it happens the most when it's really hot out and the plane has been sitting in the sun for a little while and especially if there is a few inch run where the rod is not inside it's tube, e.g. from the fuse to the rudder/elevator.