WASHINGTON — It seemed so simple and familiar: Spring forward, fall back. For 20 years, that’s what Americans - and their technology - have done with their clocks on the first Sunday in April and the last Sunday in October.

No longer. When few people were paying attention in August 2005, Congress lengthened daylight-saving time by four weeks in the name of energy efficiency. The change starts this year - on March 11 - and it has angered airlines, delighted candy makers, and sent thousands of technicians scrambling to make sure countless automated systems switch their clocks at the right moment.  Full Article