Seth says that for optimal health, both physical and mental, it's preferable to sleep 5 or 6 hours during the night, with a one or two hour nap during the day. Even a ten or twenty-minute doze would be beneficial.
This is something I've been practicing of late, sans the nap (although it would be nice,) and already I've been programmed to need less sleep. I have more hours of waking time, which is like getting a bonus every day, and I have more physical energy than before. But what I really notice are my dreams.
It seems that I "stopped" dreaming in the past few months, often waking in the morning feeling kind of dull, having to find my way back to myself, laboring to feel connected to my life.
I'm a firm believer that sleeping dreams help us in our daily lives. They provide a place to work out conflicts, bring to light our weaknesses, help us to walk through fears. Even if we dream that we have a thousand toes, it means something, and it's a beautiful gift to us from our subconscious that we receive over and over.