Conan said:It was first proposed by Ben Franklin as a way of saving candles in the evening. It was put into law during WWI in 1918 also to save energy in the evenings. It's been studied quite a bit, and doesn't really have any advantages. A lot of places don't use it or gave up on it, including several US territories and increasing number of states. I wonder if anyone ever stops to think whether much has changed since 1918.