Just do it Overcoming exhaustion is but one of many obstacles a writer faces. Once a structural story line is complete and the characters are speaking, it's time to get down to the business of getting it on the page.
All writers have their own approach.
Sticking to a set schedule seems to work for many writers. I'm not a machine. Every classic script is about ideas. It has something to say about life, about the human condition. The first evaluation is the writing.