There are some variables especially "age" dtermines how much sleep you would need.. Sleep is a vital part in our day to day life.
Did you ever felt sleepiness, not focusing, cramp iin your leg during meetings, class, work or anything you were doing? If you did then it was because you are sleep deprived. You are not getting the amount of sleep you need.
There was a research conducted by NSF(National Science Foundation) and with information from that they released the optimum time of sleep a person needs according to their age.
Newborn babys - 14-17 hrs
Infants - 12-15 hrs
Toddlers -11-14 hrs
Preschoolers -10-13 hrs
School age - 9-11 hrs
Teenagers - 8-10 hours
Younger adults - 7-9 hours
Adults - 7-9 hours
Older adults - 7-8 hrs