For as long as the practice of adapting daylight hours has been in existence, the practice has been controversial. However, of the countries that participate in the practice each is attempting to develop ways to conserve energy and better society through the practice.

The practice of adapting daylight hours first surfaced in the ancient world and was again popularized in 1784 by Benjamin Franklin in satirical writings but it was William Willett, a prominent English builder and outdoorsman that promoted the practice that would become known as Daylight Savings Time or DST for short.

Willett supposedly came up with the idea of adapting daylight hours in 1905 after he noticed diminishing daylight during his outdoor sporting events. His solution for the diminishing daylight problems—advance clocks during the summer months so that afternoons have more daylight and mornings have less.

With his own money, Willett published a pamphlet on the subject entitled "The Waste of Daylight," in which he proposed that clocks be advanced by 80 minutes in the summer. The additional daylight hours would increase time for recreational events and save 2.5 million pounds in light costs. He also proposed clocks be retarded by the same number of minutes in September.

Willett promoted his proposal to various members of the British Parliament including Robert Peace and a young Winston Churchill. At first in 1909 the Parliament reviewed then dropped the bill; but finally after the outbreak of World War I, when the issue became more important in order to save coal the bill passed on 1916, the same year Germany began the practice. In Britain clocks were advanced an hour on May 21 as a wartime production-boosting scheme under the Defense of the Realm Act.

Soon other European countries adopted the practice too. The U.S. adopted the practice in 1918. Though each country and sometimes even different areas of each country have developed their own rules regarding Daylight Savings, typically clocks are adjusted forward one hour near the start of spring and are adjusted backward in autumn.

For most of its existence the practice of Daylight Savings Time has been controversial. While there are many pros to the practice, there are also many cons. Adding daylight to afternoons benefits retail business, sports, and other activities that exploit sunlight after working hours, but causes problems for farming, entertainment and other occupations tied to the sun. Read more about how Daylight Savings Time affects the financial world in BusinessWeek, Money Magazine, Kiplinger’s, Forbes and The Economist.

One of the many pros argued for Daylight Savings Time is traffic; studies show that traffic fatalities are reduced when there is extra afternoon daylight. For more pros on Daylight Savings Time read articles in magazines like Newsweek, Time and The Economist.

Limited research on many other affects is a major problem for making the argument for DST. One of the early goals of DST was to reduce evening usage of incandescent lighting, once the primary use of electricity in most households, research about how DST currently affects energy use is limited and often contradictory.

And then there are the challenges shifting the time presents such as complicating timekeeping; disruption of meetings, travel, billing, recordkeeping, medical devices, and computerized equipment. Many computer-based systems can adjust their clocks automatically, but this can be limited and error-prone, particularly when DST rules change.

To complicate things more in terms of DST, starting in 2007 clocks were set back three weeks earlier than usual. U.S. Congress introduced a provision in the Energy Policy Act of 2005 in an attempt to save electricity mandating that clocks "spring forward" three weeks earlier, on the second Sunday in March, and "fall back" a week later, on the first Sunday in November. Though many anticipated this new time change time, Time magazine reported the headaches the change caused were worth the conservation of energy.