Ask people how many hours they need to sleep each night and most will not provide the same answer. Some might tell you that they cope well on 5 hours while others respond by saying that they need at least 10 hours sleep or they do not feel human. However, most experts recommend adults sleep between 7 and 8 hours per night, although some suggest that sleeping half-an-hour less or up to an hour more is beneficial. Knowing how much shuteye you are supposed to get can be confusing.

The number of hours scientists and medical professionals propose people sleep stems from evidence regarding time spent sleeping relating to health and mortality. Studies show that people who sleep under 6.5 hours per night, or greater than 7.5 hours, have a shorter lifespan than others do.

Unfortunately, time recommendations do not take into account individual needs. It might be that your genetics or lifestyle makes your sleep requirements different to the norm. However, not enough research has been carried out on the subject in order for people to be certain how to establish the individual demands of their system. Nonetheless, common sense might tell you that if you feel sleepy and groggy during the day when you have had 6.5 hours sleep at night, you probably need to sleep for a longer period. Likewise, if you sleep for 9 hours, but feel bad, sleeping an hour or so less might be wise.

Although it is not sensible to become obsessive and paranoid about whether you sleep enough because stress can make you ill, it is wise to keep a watchful eye on your sleep patterns relating to your health. It might be that you catch colds more often when you sleep poorly, or that you cannot cope with the ups and downs of everyday life. On the other hand, maybe you just cannot get your head together and think straight after having a long lie in at the weekends; adjusting time spent in bed could improve matters.

Adopting a regular bedtime/wake schedule will help you attain similar sleep times each night. However, other factors in your life such as stressful events and excitement, and even what you eat could affect the quality and length of sleep you experience.

You cannot control every aspect of your sleep, but you can be healthily aware of how the length of time you sleep affects you. Going to bed and rising at set times, and adjusting time spent sleeping according to your needs will mean that you get the slumber that you need.

References:
http://content.time.com/time/health/article/0,8599,1812420,00.html
http://news.bbc.co.uk/1/hi/magazine/6546209.stm
http://www.mayoclinic.com/health/how-many-hours-of-sleep-are-enough/AN01487