Ever watch American idol? Not the ones that are in the finals, but rather the ones that don't go past the first audition. Most people are tone deaf. I think they are the ones that can't set a needle.

I've been in a half dozen clubs over the years. Every club has one or two guys that run run run and tune tune tune. Total hacks every one. You can adjust their setup and they get a great flight, but the next time up an half hour later, they are on the needle again.

I usually fire up, do a simple pinch test if the fuel line is exposed, and fly. If it sounds good in the air, then finish the flight. Otherwise, just land and turn the needle a whole click and go again. The most I ever have to change a sport engine is two clicks. When in doubt, richen up.