Below, Steve Ditko casually mentions being taken off Spider-Man and Dr. Strange “at times.” But when would that have been?
"Those fans who continually moan about my quitting Marvel, Spider-Man and Dr. Strange, act as if Marvel was/is a southern plantation ruled by The Divine Right to Own Individuals as Slaves and that I, as a freelancer (not an employee), could at any time be (and was at times) taken off the S-M/DS strips, and given no work, had no right to quit and that I should be made to go back, be made to keep producing story ideas, panels, pages of story art and comic books for their gratification. Only they are free to act as they choose without penalties."
—Steve Ditko, “The Ever Unreachable,” 2009