Day Light Savings Time is a change in the standard time with the purpose of making better use of daylight and conserving energy. The DST schedule in the U.S. has been revised several times throughout the years. From 1987 to 2006, the country observed DST for about seven months each year. The current schedule was introduced in 2007 and follows the Energy Policy Act of 2005, which extended the period by about one month. Today, DST starts on the second Sunday in March and ends on the first Sunday in November.