A good sleep is a multiplier of energy. It will determine how much you get done tomorrow, how you interact with other humans, your happiness. Frankly, sleep is magic. But, like all magic, it doesn’t take much for it to vanish. You know how you work best, but you have already worked out you can’t do it without sleep.
These things work:
Eight hours to work. Eight hours to sleep. Eight hours of recreation. Eight hours of quality sleep increases your ability to gain new insight into complex problems by 50%.