sell-by date vs shelf life

sell-by date

noun
  • The final date on which a perishable product can be legally sold to the public. 

  • Used to indicate that something, or someone, is old and out of date. 

shelf life

noun
  • The length of time a product (especially food and drugs) will last without deteriorating or without being sold. 

  • The maximum time a packaged material can be stored under specific conditions and still meet the performance requirements specified. 

How often have the words sell-by date and shelf life occurred in a corpus of books? (source: Google Ngram Viewer )