That's my attitude. If you notice any symptoms in your plane that can be cause by vibration then revisit prop balance. If the glow plug is blurry that's a good indicator. Usually the engine runs rougher at lower throttle settings and that has a lot more to do with the engine than the propeller. An easy way to tell is just run a spinner with no prop at idle. Won't hurt the engine as long as you don't throttle up. I used to polish aluminum spinners that way.