In modern tennis players know how to watch the ball. However, doubles offers the unique opportunity, because of a netman, to disrupt the flow of play. See the attachment below.
When confronted with a losing pattern of play, nearly all competitive tennis players understand that they need to make a change. The point of this short piece is to illustrate that this change must always be undertaken with a strategic foundation and not simply be a different look meant to confuse the opposition.
In the post-modern world any doubles formation can be justified by the matchups on the court. I will go over a few so that you have a better idea of how and when to use them.