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 (such as farming) or to darkness (such as fireworks shows). Although some early proponents of DST aimed to reduce evening use of incandescent lighting (formerly a primary use of electricity), modern heating and cooling usage patterns differ greatly, and research about how DST currently affects energy use is limited or contradictory.
DST clock shifts sometimes complicate timekeeping and can disrupt meetings, travel, billing, record keeping, medical devices, heavy equipment, and sleep patterns. Software can often adjust computer clocks automatically, but this can be limited and error-prone, particularly when various jurisdictions change the dates and timings of DST changes.