<P> By synchronously resetting all clocks in a region to one hour ahead of standard time, individuals who follow such a year - round schedule will wake an hour earlier than they would have otherwise; they will begin and complete daily work routines an hour earlier, and they will have available to them an extra hour of daylight after their workday activities . However, they will have one less hour of daylight at the start of each day, making the policy less practical during winter . </P> <P> While the times of sunrise and sunset change at roughly equal rates as the seasons change, proponents of Daylight Saving Time argue that most people prefer a greater increase in daylight hours after the typical "nine to five" workday . Supporters have also argued that DST decreases energy consumption by reducing the need for lighting and heating, but the actual effect on overall energy use is heavily disputed . </P> <P> The manipulation of time at higher latitudes (for example Iceland, Nunavut or Alaska) has little impact on daily life, because the length of day and night changes more extremely throughout the seasons (in comparison to other latitudes), and thus sunrise and sunset times are significantly out of phase with standard working hours regardless of manipulations of the clock . DST is also of little use for locations near the equator, because these regions see only a small variation in daylight in the course of the year . The effect also varies according to how far east or west the location is within its time zone, with locations farther east inside the time zone benefiting more from DST than locations farther west in the same time zone . </P> <P> Although they did not fix their schedules to the clock in the modern sense, ancient civilizations adjusted daily schedules to the sun more flexibly than DST does, often dividing daylight into twelve hours regardless of daytime, so that (for example) each daylight hour became progressively longer during spring and shorter during autumn . For example, the Romans kept time with water clocks that had different scales for different months of the year: at Rome's latitude the third hour from sunrise, hora tertia, started by modern standards at 09: 02 solar time and lasted 44 minutes at the winter solstice, but at the summer solstice it started at 06: 58 and lasted 75 minutes . After ancient times, equal - length civil hours eventually supplanted unequal ones, so civil time no longer varies by season . Unequal hours are still used in a few traditional settings, such as some monasteries of Mount Athos and all Jewish ceremonies . </P>

What was the original purpose of daylight savings time