That time of year, when clocks spring ahead (CBS/AP) It's time to "spring ahead" - and lose an hour of sleep. This weekend most of the U.S. makes the switch to Daylight Savings Time, moving clocks ahead one hour in order to ensure an extra hour of sunlight each evening. The official change is at 2 a.m. local time on Sunday, March 11, 2012. Not everyone in the U.S. makes the switch from standard time. Hawaii, Arizona outside the Navajo Indian territories, Puerto Rico, the Virgin Islands, American Samoa, Guam and the Northern Marianas stay on standard time. On November 4 you'll switch your clocks from 2 a.m. to 1 a.m. and get your lost hour of sleep back - so you'll be well-rested in time to vote on Nov. 6. State emergency officials suggest you use the bi-annual occasion as a reminder to test your safety equipment. For example, check the batteries in your smoke detectors and carbon-monoxide detectors, and replace the batteries if necessary. And if you don't have the detectors, now's a good time to buy them. You should also update your emergency kits. Officials recommend that everyone keep a basic kit at home with enough food and water to last your family for three days, along with a radio, flashlight and first-aid kit. Daylight Saving Time Rules (National Institute of Standards and Technology)