I worked 17 hours yesterday. That was done on about 3 hours of sleep.
I hate having to sleep. This doesn't mean I hate sleeping. Hell, I love sleeping. But I can tell you that if you're not enduring a certain amount of sleep deprivation you're not living a full life.
I find that 4 to 6 hours a night is just fine. I feel great on that much sleep, and it doesn't really affect my performance. 8 hours is deemed the right amount of sleep, but I get lazy on that much. It seems the more I sleep the sleepier I become.
I've also learned the power of the 20 minute nap. In those 20 minutes, I can start over again. This strategy is what has gotten me home on many occasions when I have dipped too hard into my reserves.
I've also found that I can sleep just about anytime and anywhere. It doesn't matter if it is sleeping or sitting, couch or concrete. I can always cop a few Z's. I'm convinced that humans evolved to sleep like this but modernity keeps us from doing it. Like Edison and da Vinci, I could go through my day with just a series of naps here and there.
I can also tell you firsthand that sleep deprivation slows reaction time and thought processes and will cause hallucinations. At this stage of the game, your batteries are drained. It's time to stop and recharge.
I really like the battery analogy when it comes to sleep. I am always charging my cellphone, and I can't help but notice the parallel between my body and that appliance. One of the things I've learned is that you can cheat sleep by going for longer periods between sleeping. Like a battery, you still take the same amount of time to recharge no matter how depleted you are.
Finally, I call the urge to sleep an attack of the "sleep demons." They usually strike after a heavy meal, reading a hundred pages of text, or watching a ball game. It is a game of inertia between me and the sleep demons. If I slow down, they gain an edge. If I stop, they win. But losing isn't so bad. I usually wake up feeling great anyway.