The concensus at my club is that balancing is really only necessary for large props, especially wood props, and even then some guys don't bother. I've flown electric and nitro planes for a couple of years now, and I've only balanced props on my Super Tigre G2300 (a 1.4 size engine). If you have a balancer and don't mind taking the time to do it, go for it, it can only help. If I ever get more vibration than normal from one of my setups, that's probably the first thing I'd do (check prop balance), but I've not had that problem yet.