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If you need an alarm to be able to wake up on time, you almost certainly aren't getting enough sleep. And as an additional incentive, it has been scientifically proven, that it is healthier to be woken by natural light.

People who set alarms that don't end in 5 or 0 are usually either extreme procrastinators or extremely busy. Under normal circumstances you should always set an alarm earlier than necessary in order to be ready when it's time. Setting an alarm that doesn't end with a nice number like 5 or 10 would force your brain awake and give you a feeling of perpetually being late.

If you need to set multiple alarms, because you're worried that you'll miss it if there's only one, you should try getting a bit more sleep.