First a word about ball machines. For the majority of beginner and intermediate players, whether the goal is to win matches or to have fun rallying, the key is to be able to hit the ball consistently. At this level of play, the way to win is not to make errors. This is where practicing with ball machine comes in. Consistency can be achieved by hitting the same stroke repeatedly. With a ball machine the player can practice ground strokes, volleys, high balls, low balls. Baseline shots, approach shots, running forehands, running volleys all are easy to set up with a ball machine. Practicing directional control and depth control is easy. It's all a matter of how much time one spends on the ball machine. From experience, I can say that practicing with another player of the same level is not that effective. Practicing with another player who is much better is too boring for the other player. So in summary I firmly believe in using ball machines to practice.For 3 months I cancelled all my lessons and practiced with the machine; now my coach said there is a big improvement in my play. My machine so far has not had any problems at all.