At 2 a.m. on Sunday, Nov. 4, most U.S. residents will be moving
their clocks back an hour to mark the end of Daylight Saving
Time. Not all states, however, will observe the time change.
Residents of Arizona, Hawaii and U.S. territories like Puerto
Rico, Guam and the Virgin Islands will remain on their normal
schedules. In the U.S., the upcoming time shift is part of a
longstanding tradition in which most residents set their clocks
ahead an hour in the spring ("spring forward") and turn them
back an hour as winter approaches ("fall back"). The idea behind
Daylight Saving Time is to use the "extended daylight hours
during the warmest part of the year to best advantage." The time
shift is said to reduce the need for lighting during the
evening, which is why the changeover is considered an energy-
saver. However, experts are divided as to whether or not this
true. According to National Geographic, several studies
conducted in recent years have suggested that Daylight Saving
Time "doesn't actually save energy and m