how long vs long-drawn-out

how long

adj

  • Used literally: what duration. 

  • Used literally: what length. 

adv

  • Used literally: for what duration. 

long-drawn-out

adj

  • Protracted, extending for a great period of time. 

How often have the words how long and long-drawn-out occurred in a corpus of books? (source: Google Ngram Viewer )