I think that the "3 balls ahead" adage means different things depending on the skill of the player. For an absolute beginner, it's something to get them from blindly firing away at whatever shot they have without considering position play at all. For a player that has learned basic position play, it gets them to start thinking in patterns, albeit short ones. For advanced players, it's a reminder to play position on the right side of the ball to get to the one after it as you are running balls.
In any case, I think that it still has to be paired with other advice about playing to break out clusters or defensive play; playing shape "3 balls ahead" just makes sure you can get from ball to ball when they are sitting out in the open.
In any case, I think that it still has to be paired with other advice about playing to break out clusters or defensive play; playing shape "3 balls ahead" just makes sure you can get from ball to ball when they are sitting out in the open.