When people are tired, they tend to overlook what is important or what could be important. People who are tired tend to miss out on the small details that could have been huge benefactors in the long run. Tiredness can also lead to careless mistakes that can decrease the value of your content. Poor writing can overshadow good content because it shows carelessness which only results when a person is tired. If you are only getting less than 9 hours of sleep per day, then you need to change your schedule.