"Artificial light doesn't only deprive us of a feeling of night and darkness, and disrupt our circadian rhythms, but it disrupts the timekeeping of other species too... The things we are doing have a ripple effect in the way other species are able to function and keep time." 

David Farrier

Not only does this conserve energy usage, but turning off unnecessary artificial lighting can be preserve your circadian rhythm. This is better for your sleep and productivity but David Farrier says it puts you in touch with natural temporal ryhthms and cycles. This can have a profound impact on how you view your actions and place within the wider natural world.