sustenance vs upkeep

sustenance

noun
  • Something that provides support or nourishment. 

upkeep

noun
  • Maintenance; the act or effort of keeping something in good and working condition. 

verb
  • Do you know how to upkeep a boat? 

  • To maintain (something) or keep it in good repair. 

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