I have through chapter fourteen written on this next book.  I am sure some of these chapters will be expanded when I go back through.  So far, I have about thirty chapters planned, but that will likely change.  It always does.  I can have the best laid-out plans, but once the story starts taking shape as it is written, those plans often change.  I think of something new to incorporate, or I run into a problem where the previous plans will not work.  Chapters are added.  Some chapters are combined or removed completely.  I hope to have another few chapters written this week, but it will all depend on how busy things are at home.