A misconfigured or untuned lighting system can result in excess energy usage with lights left on for longer than necessary, or at brightness levels higher than what is required for the space.
New lighting layouts are often designed to over illuminate the space, the reason for this is to accomodate the decrease in light output of the fixtures over time. Unfortunately for the users of the space, the lights are often left at full output causing visual discomfort. A lux level report of the the space can identify areas of the facility that need to be dimmed down, and sometimes dimmed up, to provide the correct amount of light for the working surface.
The type of work area will determine the required lighting levels, for example, a typical office space should have between 320-400 lux on the desk. Light fixtures near the windows can be set to automatically dim/brighten in response to the ambient light levels while maintaining the desired lux levels on the working desk.