early days vs early innings

early days

noun
  • Initial stages of a project. 

  • A time too soon to make a decision or come to a conclusion. 

  • The initial period of an innovation 

early innings

noun
  • The early stages of any project or extended event. 

  • The first, second, and third innings. 

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