The lead-time for launching your book will vary depending on your purposes and resources. If you are building a career as an author, it might also depend on whether this is your first book launch or not. The formula for viability as an author is simply books x readers = sales. That explains in part why publishers will tell you the best marketing for your book is always your next book.
But let’s back up a bit. If you are a first-time author and have no readers, how do you get them? One way is to publish a book with the target of lots of reviews rather than sales, initially, and then use that first book to build a readership with. Then with book two you’ll have more options and can start focusing more on sales. Book sales and being an author as a career is a long-term plan, despite the occasional lightning strikes. For a professionally published and marketed book launch I’ve seen publicists want anywhere from three months to a year to prepare. As you learn about what’s involved you’ll see why.
The other end of the spectrum is the “soft launch,” where a title becomes available quietly in the night, without fanfare, and this suits plenty of authors, too. Remember, launches and marketing take either sweat equity or actual cash, so a soft launch might be the best way to start if you have little of either, or if the book is for establishment purposes like credibility and positioning. They still work wonders!
And when you learn a launch is primarily about reviews, the whole pre-launch sequence starts to make lots of sense. Otherwise, your fresh, new, well-written tome might simply drift unnoticed, a message in a bottle, a drop in an ocean. There are now over one million books published each year, so crafting a smart launch and long-term plan for your books is a great idea.