Which side should a close-board fence be positioned Best side in neighbors or owners What if they are paying half as they want the fence changed but the existing one is still ok?

The law requires that the best side (the side without all the wooden posts showing) be towards the neighbor. it makes no difference if they are paying half, because the law requires that the owner of the fence follow the law. in other Words, the fence is on your land, and therefore, the best side must be towards the neighbor. The law protects not only the neighbor, but future buyers of your neighbor's property.