How long does it take to write a book?

The average time it takes for an author to write a book is six months. Of course, books can be written much faster (I've written one in a couple of days) or much slower (it took me 8 years to pull together Public Speaking Super Powers). Why the wide range? It all depends on the book, the style of writing, how many words, and the author's time put into butt-in-seat writing.

Regardless, writing a book is an effort. And there are always ways to decrease effort while maintaining quality.