One "hidden value" of balancing props is that you discover the bad ones before you put them on your airplane.

Most times nowadays, props are pretty well balanced. But you WILL find some that are lousy. And the WILL beat your RX and servo's and airframe to death. Sometimes slowly, sometimes fast.

There is a dead cheap way to make your own balancer. A piece of dowel that just fits your prop with a small hole in the center with a string through it works great. Glue a washer to one side of it to keep it from slipping through the prop.

To use it, thread the string through the prop's hole. Pull the dowel into the hole, and the washer stops it there. Hold the string and let go of the prop and it'll hang down with the heavy blade hanging further down than the light one.

I made myself a couple of these puppies. One fits props. I take it with me to the LHS when I'm buying props. Why buy the bad ones? I leave them at the hobby shop for the guys who think you don't need to balance props nowadays. Another one I made is larger. It fits my lawnmower blade. I sharpen the thing every year and balance it true. Someday I'm gonna put a tuned pipe on the sucker and start running 40% nitro and have lots more time to fly. I wish APC would make lawnmower blades.