There is no clear cut answer to this question as sleep requirements depend on the person. Experts provide general figures for each age group, but the accuracy of these numbers still depend on individual needs. For an adult, around 7 to 9 hours of sleep a night should be enough. What you ought to do is observe your own sleeping patterns and see how you feel after a certain amount of sleep. Pay close attention to your mood, energy level, and overall health after a night’s sleep. This way, you can determine the optimal number of hours that you need for a good night’s sleep.