One of my work positions is being a member of the Work Environmental Committee and one of the videos I created and edited was about that in the context of the office. So I researched and the information on lighting had some interesting points. The cost of turning an incandescent light on is much as being left on for a minute. A flourescent light takes 15 minutes, LEDs it takes a long time. So If a room lit with an incandescent is going to be unoccupied for any length of time you save money by turning the light off. For a Flourescent a gap of less than 15 minutes means there's no need to turn it off and for an LED you could easily keep it on for at least an hour with minimal cost impact.

I know I'm not writing this comprehensively but I'll have to re-write it later as I have to go to work now....