Janie,
I have obstructive sleep apnea. It should be noted, though, that normally if I lay on my side I'm okay.

some medical conditions make a person not able to sleep well, and these conditions need to be addressed. If one regularly, naturally sleeps only a few hours a day you may want to consider a thorough medical exam. Possible medical problems that come to mind for causing little sleep can be creating other havoc in your body are reactions to medication, stress, thyroid disorders or depression, all of which can be corrected.

Like thekai said, the amount of sleep we need to feel refreshed varies from person to person. However, the long term effects of not getting adequate sleep can be as dramatic as a shortened life expectancy. So, it may "seem" like a waste of time to some, but in the end, it all balances out. Personally, I try to get 8 hours of sleep a night, but that rarely happens. Usually 7 is what I do get, and there's still plenty of time in the day to do what I need and some :)

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Who needs sleep?
It's 3:15 AM as I write this. Up at em in 5 hrs. I only need 4-5hrs of sleep. Can't believe some people actually sleep 8-10hrs. What a waste.

I think different people require different amounts of sleep. With children, it is almost universally important to get plenty of rest. With adults, I think it is much more variable. For example, I can go with four to six hours of sleep and feel just fine. If I sleep more than that, then I feel like I have wasted my time and exercised poor time management. Even times when I don't set my alarm clock, it is rare that I sleep more than eight hours.
The same can not be said for everyone, though. I have many friends who have been known to sleep for 12 hours, and sometimes longer, if they didn't set an alarm and had no plans for the next day. Some people will always feel fatigued if they don't get at least 8-10 hours of sleep.
This being said... if the definition of "enough sleep" implied is the medical definition of a healthy amount of sleep (it's still defined as 8-12 hours, isn't it?), then I do not consider getting enough sleep a high priority for myself. I consider it a waste of time.