The United States shifts its clocks back one hour at 02:00 A.M. today, Nov. 7. Are you prepared? Chances are that you are.

We go through time switches twice a year, so you'd think we'd all be experts at shifting our lives an hour forward or an hour back.
And yet, everyone has stories of forgetting to adjust that one crucial clock, or of the coworker who showed up to work an hour early or an hour late on Monday.
This year, the only people that probably need to worry about Daylight Savings Time are those that use an iPhone, don't read technology publications, and work Sundays or Mondays. That's because an unpatched iOS bug in the alarm-clock app failed to take into account the time change, meaning that those with recurring alarms won't wake up at the proper time, just as those users in Europe and Australia did.
For Sunday and Monday workers, Apple recommends that users simply turn off their recurring alarms and manually set their alarm Sunday night, manually accommodating the time change by setting their alarm an hour late. The glitch should fix itself on Monday morning.
(Why? Because an alarm set for 07:00 AM on Saturday was to go off at 06:00 A.M. today. Think about it this way: you have to set your clock back sometime, and you could either do it Saturday night - or postpone it to Sunday/Monday morning, when your alarm rings at 07:00 A.M. But if you set the clock back Sunday morning when you wake up … it's 6 AM.
So at 2 AM Sunday morning, or whenever you go to bed Saturday night, turn your clocks back by an hour. It's also recommended that you replace your smoke alarm batteries twice a year, and the twice-a-year time change is a convenient time to remind yourself to do that.
For the tech obsessed, Daylight Saving Time gets a bit more complicated each year as our pockets and desks fill up with more and more tech gadgets. And Congress hasn't made the shift any easier. The 2005 Energy Policy Act changed the start date of Daylight Saving Time beginning in 2007. This affected the auto-updating clocks on some tech products purchased before that date, including operating systems. Hopefully everything runs smoothly for you by now, but just in case, here are some things to consider:
-- Some gadgets, like your phone, will be automatically updated by syncing with your cellular network.
-- Others, like some iPods, base their clocks on whatever time your PC says it is.
-- Unconnected devices like your watch or clock radio will likely need to be updated manually.
-- Still others, like your computer, are hopefully patched to correctly update at the appropriate time, but may not be.
However, if your OS clock still isn't patched for the Daylight Saving Time change from a couple years ago, you're probably running a very old operating system, or an unpatched version of XP that's pre-SP2, or you're running a version of Vista that has never been updated. If any of these scenarios are the case, there are plenty of reasons to update your OS as soon as possible, and correcting your PC's clock is actually pretty low on that list.
(Source: PC Magazine)