My granddaughter is a nightmare when it comes to switching lights off. She will even switch them on when it is broad daylight and leave them on. While I know that many people will think this is unimportant I think it adds up over time. My father was very strict when we lived at home and drummed it into us that we would have to contribute towards the bill if we kept leaving lights on. This has no impact on my granddaughter so I am still thinking of ways to try and train her to do this.