How long does it take to write a book?

One piece of writing advice I’ve heard is that if your book
takes more than a year to write, then you should dump it and start another one.
I can see some merit in a very small part of this, but no, if
we dumped our novels after twelve months, we’d have a string of unfinished
stories behind us.
I think where the advice comes from is that you shouldn’t take forever to write your first draft. Stephen King says three months, which would be nice if you can do it, but a lot of us can’t. I’m more in favor of so long as you keep plodding along, and getting further into the story, then keep writing.
In an ideal world, the first draft is written quickly. But remember, for many people, that first draft is very basic. Many of them are skeletons of what is to come, way short of the word count. For others (like us) they’re often the opposite. Long, rambling epics we need to trim. The most important thing is that you keep writing.
Many non-writers are surprised at how long it takes to write
a novel. Ours certainly take a long time.
Years. Unless we’re under a deadline,
and that speeds things up considerably.
Let’s look at the timing of some of our books.

Linesman
Started: 18 July 2010
Finished draft 1: 29 January 2012
Four months and four drafts later we sent a draft to Caitlin,
who’d just become our agent.
For the next year we wrote new stories while the novel did
the rounds with the editors. Then, when it
looked as if Linesman wasn’t going to
sell, we did a major rewrite at the agent’s recommendation, from the feedback
from the editors. Our final version was completed in September 2014.
All up, four years.

Alliance
Alliance was written
under contract, and we hadn’t started it before we wrote the contract. It’s one
of the fastest books we wrote.
Started: 16 February 2014
Finished draft 1: 7 December 2014
Final to editor: 10 August 2015

Confluence
Likewise, Confluence
was written under contract and we hadn’t started it prior. We were still finishing this the day before
we sent it through.
Started: 1 February 2015
Final to editor: 21 May 2016
I don’t have a first draft completion date for this one.

Stars Uncharted
We started Stars
Uncharted while Linesman was doing the rounds to editors, before Anne (editor)
had asked for a three-book series about Ean Lambert. Linesman
didn’t look as if it would sell, so Caitlin (agent) suggested we write something
else altogether. (We weren’t sitting
around before that, by the way, we were writing stories in the Linesman
universe, but not series books.)
Started: 15 August 2012
Finished draft 1: 1 August 2013
Started the rewrite: 4 April 2016
Final to editor: 9 May 2017

Stars Beyond
Stars Beyond has
had a few changes. It, too, was under
contract, but because the time between books was so long, we had plenty of time
to write it. Except, that we went off on a tangent, then went off on a
different tangent, and finally found our path very late. Our original delivery
date was 31 May 2018.
Started the original story: 24 February 2017
Rewrote after talking to editor: 29 October 2017
Sent to editor (and agent): 31 May 2018
Agent recommends rewrite: August 2018
Final copy sent to editor: 31 January 2019
As you can see. It takes us a while to write a book.