(How's that for an inflammatory title?)
People have strong feelings and routines about alarms. Some people love snoozing, others wake up at the first ring, and others hate being woken by an alarm so don't set one at all.
If you need an alarm to wake up every morning (and you don't have to wake up at 4 to be at work by 5), it's likely because you're not sleeping enough, or other factors are eroding your sleep quality or general health. A few common factors: - Sleep apnea, often signaled by snoring - Anemia, causing overall fatigue in spite of sleep - Circadian rhythm disruption, due to an irregular schedule, travel, screens at night, being indoors all day, extreme latitudes, or vitamin deficiency - Anxiety and unfinished business - Alcohol, caffeine, and medications
Sleep cycles contain a higher proportion of REM or dream sleep as the night goes on. A sleep cycle lasts about 90 minutes. Using an alarm to get up after just 6.5 hours of sleep (10:30-5) rather than sleeping for 8 hours is quite common. The catch is that in addition to missing out on overall sleep, which in itself contributes to fatigue, poor eating habits, etc,... you're missing out on the cycle that would probably have the most REM sleep, which has significant effects on mood. It's possible to create a clinically diagnostic level of anxiety in a normal person after just one night of sleep deprivation.