O, how I faint when I of you do write, Knowing a better spirit doth use your name, And in the praise thereof spends all his might To make me tongue-tied speaking of your fame.
You read what you have written and, as you always stop when you know what is going to happen next, you go on from there. You write until you come to a place where you still have your juice and know what will happen next and you stop and try to live through until the next day when you hit it again.
After the Beatles and Dylan, there's this assumption that you are a singer-songwriter, or that if someone else is writing your rhymes, you're a fake rapper.