There is no way to determine if your engine is set correctly without moving the needle valve. Having said that, I check it when I first start it on any given day, and then leave it alone for the day. If I see dark oil residue building up on the plane, I'll richen it a click. If it seems to be hesitating on spoolup, I'll lean it a click.

I never mess with the low end mixture once I have the engine running well.

Brad