I don't know why guys shave their leg hair unless they're a triathlete or participate in at least one of the sports! But even then, they would probably do the whole body. Unless your leg hair is a couple inches long, I don't see why you would even trim it. :/
Just a question, why do you want to get rid of the leg hair?? The one hairy part on my body I would NEVER shave or wax would be my legs. :O I could live with practically anywhere else I would usually not shave - chest, belly, and arms - but leg hair I would want to keep.