You would think that the simplest and easiest way to save money on your home lighting bill is to turn the lights out when you leave a room. Well, it's a bit more complicated than that. Did you know every time you turn a light on and off, it shortens the bulb's operating life? While you might be saving money on your electric bill, you will also be spending more on new bulbs [source: EnergySavers.gov].
At the end of the day, however, it's still more cost effective to turn the lights off even if you're constantly replacing them. In the summer, turning off the lights will keep a room cooler, allowing you to save money on air conditioning [source: EnergySavers.gov].
Fluorescent bulbs are a bit more complicated. According the U.S. Department of Energy, if you're leaving a room for more than 15 minutes, turn out the lights. If not, keep the lights on. Why? Fluorescent lights are more expensive, and like other bulbs, switching them on and off limits their life. It's better to eat the additional energy cost than to continually buy new fluorescent bulbs [source: EnergySavers.gov].