John McWhorter, explaining why he is publishing chapters from what he sees as his new book (he is still unsure about the title, the current working one is The Elect, and it's a social commentary rather than popular linguistics): "I have a book coming out about profanity ... called Nine Nasty Words, that's coming out in May, and contractually I can't release another book hot on the heels of or right behind that; that's not the way these things work."
(from a conversation with Michael Shermer)
Before I heard him say it (in a different conversation a bit earlier), I had no idea that releasing books too frequently can be a problem too.