Sometimes it's impossible, we know. But so-called "fragmented sleep" -- even when it goes on for hours -- is not physically or mentally restorative, and it causes daytime drowsiness. It also dramatically compromises learning, memory, productivity and creativity. Many people use snooze bars thinking that they'll get an extra hour of sleep after the first alarm goes off. Wrong! If you set the alarm to ring every 15 minutes for an hour, you might get 18 to 20 minutes worth of fragmented sleep. It's much better to go to bed one hour earlier and wake up naturally.