If you use wood props you will need to balance as wood densities will affect balance. The compsite props are a lot more consistant out of the package. APC's are particularly good. Although once in a while you'll find one way out of wack.
It's important to at least check the balance. If you have a prop that is way out of balance at 10,000 rpm the vibration from it is transfered to the airframe and radio. And that's not good. The smoother everthing runs the longer it will last.
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