The direction of installation of the herringbone floor depends on the shape of the room, the incidence of (sun)light and your personal preference. The rule of thumb is that you install wooden floors in the direction of the incoming sunlight, but in practice the (sun)light can come from several sides or the shape of the room doesn’t make this desirable. When light comes in from several sides, you can install the herringbone floor in the living direction.
In narrow spaces, such as a hall or kitchen, the herringbone floor is usually installed lengthwise. In wide or square spaces you can see where the light comes from to determine the installation direction. Finally, you can also turn the herringbone floor a quarter turn. In this way you get the so-called 'elbow pattern'.