This pattern changed as he became a professional. He found that it was important to start learning lines right away -- starting with the second day of rehearsal.
Nowadays, usually about a month before the actual rehearsals begin, he starts to memorize the lines. Using a small tape recorder, playing all the parts, he tapes all the dialogue. He works for a few hours everyday, pausing the recorder, reciting his own lines in the appropriate sequence, checking them for accuracy.
Later, every day before each and every performance, in his dressing room, John Cullum goes over the lines of the play.