I'm a college student and don't get much sleep, how do I know if im getting enough sleep?

Signs of Poor Sleep. On average, you should be getting 6-8hr of sleep. Common signs of not getting enough sleep are waking up tired, feeling tired throughout the day, having trouble focusing, & getting sick more often (e.g., colds). Sleep is very important for brain function. Pulling an all nighter for a test may seem like a good idea, but lack of sleep makes it harder for your brain to retain & recall info.