I agree. There are many tricks of the trade that calculations can't help you with, either. 36" 90*s, pulls are better through rigid 90*s than pvc, swabbing the conduit with a soapy rag before the pull, etc. On long underground runs, I like to blow the conduit out with an air compressor. I've blown out welding rods, soda cans, and trash before, not to mention the water that accumulates in it.
