How Long Is Too Long To Market A Book?

"But how long should you stick to marketing one book before moving onto the next? The answer depends on a lot of things. Topic, for one, will often drive the wheels of a campaign and it’s often said that the best way to market your first book is with your second and third and forth – and well, you get the idea."

http://amarketingexpert.com/ameblog/marketing/how-long-is-too-long-to-market-a-book/