Daylight saving time or summer time is the practice of advancing clocks during summer months by one hour so that light is extended in the evening hours, and sacrificing normal sunrise times. Typically, users of DST adjust clocks forward one hour near the start of spring and adjust them backward in the autumn to "normal" or regular time. New Zealander George Vernon Hudson proposed the modern idea of daylight saving in 1895. Germany and Austria-Hungary organized the first implementation, starting on 30 April 1916. Many countries have used it at various times since then, particularly since the energy crisis of the 1970s. The practice has received both advocacy and criticism. Putting clocks forward benefits retailing, sports, and other activities that exploit sunlight after working hours, but can cause problems for evening entertainment and for other activities tied to the sun or to darkness. Although some early proponents of DST aimed to reduce evening use of incandescent lighting, modern heating and cooling usage patterns differ greatly, and research about how DST currently affects energy use is limited or contradictory.