The quality of sleep is important, too. Sometimes, you get that 6 hour sleep that feels like an eternity and you are reborn when you wake up. Most of the time,

The quality of sleep is important, too. Sometimes, you get that 6 hour sleep that feels like an eternity and you are reborn when you wake up. Most of the time, we get 8 hours of mediocre sleep - guess which one's better? There also seems to be a Ballmer's peak to sleep - too little and you're deprived, but too much and you're groggy and slow. 7 hours seems to do it for me - I am well rested, yet still on that invisible edge that makes my body push harder when I need it, unlike a seemingly good 9 hours of sleep, after which I just can't seem to engage that certain drive that makes me think quick and be creative.