I read and write about eight hours a day. There is an old saying ‘well begun is half done’ ‘tis a bad one. I would use instead, ‘Not begun at all till half done;’ so according to that I have not begun my poem and consequently (à priori) can say nothing about it. Thank God!
Letter from Keats to Benjamin Robert Haydon, 10 May 1817 (while writing Endymion)