Actually, saving energy by leaving fluorescent lights on all the time a myth that may have been true decades ago, when fluorescents required a hefty jolt to get them started.
Nowadays, however, starting a fluorescent light takes only a small amount of extra electricity, so you’ll save electricity by turning the light off when it’s not needed.
Because the resistance through gas is less than with metal filaments, gas-filled tubes don’t get very hot and use about 75 percent less electricity than incandescent light bulbs. LED bulbs use even less electricity to power them.