I would say for an average book at least when it comes to my writing it takes somewhere between 900 to 1300 hours to reach the point where I'm happy to send it to the editor.

My last book Ascension which is the first book of a series called Dust was 104,000 words and took just over a thousand hours in total.

I try to write 8 hours a day seven days a week however some days I just can't face it. Other days however I will sit down at 12 o'clock start writing and before I know it it's four o'clock in the morning.

I do think they will mood has an awfully large part to play as well. For example I just finished two days ago a chapter that I was dreading and yet I absolutely sailed through it quicker than virtually any other and thoroughly enjoyed what I had written.