This is an interesting topic, and I guess I haven't read more than a few posts on it in the past.

I use the finger tip balancer. I check the balance, remove the prop and flip around, then check the balance again. I do this a couple of times to make sure it is actually the balance of the prop that is causing any motion.

I just bought a 6 pack of Master Airscrew props. I balanced 3 so far, and one needed half a blade coated in acrylic to balance, another needed a quarter of the blade covered, the third was pretty close and just needed some 'extra' plastic around the edges sanded down.

I tached my engine last time I was at the field, and got 13000 rpm at full open throttle. To me it just seems smart and safe to check the balance of a hard plastic propeller spinning at that speed.

Now RCKen has been at this a LOT longer than I have, and his advice is always spot on. If there has been a time where I didn't take his advice, I probably regretted it soon after. He does say above to at least check the prop to be sure it's not wildly out of balance, but that a very balanced prop is not necessary. There are always cases where experience beats knowledge, or where practice beats theory. Maybe this is one of those cases.

This brings up the question though of what is considered to be wildly out of balance?