due date vs timing

due date

noun
  • The date by which a task is supposed to be completed. 

  • The date on which a pregnant woman is expected to give birth. 

  • The date by which a book (or other item) borrowed from a library must be returned. 

  • The date of payment in financial arrangements. 

timing

noun
  • The time when something happens. 

  • The synchronization of the firing of the spark plugs in an internal combustion engine. 

  • The regulation of the pace of e.g. an athletic race, the speed of an engine, the delivery of a joke, or the occurrence of a series of events. 

  • An instance of recording the time of something. 

How often have the words due date and timing occurred in a corpus of books? (source: Google Ngram Viewer )