To feel completely rested, about 98% of all adults need at least 7-8 hours of sleep every night. Only a few of that 98% actually get that much sleep on a regular basis. That is due, for the most part, because most people stay up an extra your or so to get more done. The truth is, that even the slightest amount of sleep deprivation slows your speed, your ability to be creative, and your cognitive capacity. So while you may get more done, the quality of your work may suffer.