Sleeping Well
Sleep is an essential of life that some people bank on and some exploit. Eight hours sleep is recommended by experts though 6 hours is a minimum to keep up with a hectic day-time activity.
But it's a highly variable factor, which, depending on the individual, one can afford to lose some and others can't live without. Some don't mind small naps, while others can't do without an uninterrupted one.
Sleep as you like depending on its effect on your wakeful state.