First off, I don't do this personally, this is what one of my old bosses made me do. He beleived that line trimmers ran better when you only used one line instead of two. He said that the head spun faster because of reduced load. I think the opposite. First, two lines provide better balance. I could honestly feel the trimmer shake a little with one line. I'm assuming this lack of balance actually robbed the machine of power. Second, with one line, you're reducing your frequency of cut. Each time you're striking twice as much grass which should rob power and wear the line out more. The only advantage of one line I see is reduced tangling. However, a properly wound two-string timmer is just as reliable. So lets hear it. Does anyone believe that one line is better than two?