I turn off the light everytime I leave a room. I can't stand having lights on when there is no one in the room that needs to see things.
It's not always easy. In the kitchen, there is no switch. I have to pull the string and walk half-way through a dark room. Sometimes, my hands are full. And sometimes, I have to go back to turn it off.
I take full advantage of the day light hours. I don't turn lights on during the day. And, in the mornings, before the sun has come up, I flex my night vision. Hey, my cats don't need any light, those eco-friendly beasts have superior night vision.