Breaks Between Books

How long are your breaks between books?  Mine used to be non-existent.  I frequently had the next book picked out before I finished the one I was reading.  It had nothing to do with the enjoyment of my current book. Even if I found the book all-consuming, crazy-amazing, I would still have something ready and waiting.  Not that I always read the book I thought I was going to read; I occasionally changed my mind, but there still be only a day between books.  With blogging, I like to get my thoughts down before I start something new. Often, I would throw down my points and then start the new book, cleaning the post up when I had more time.  What happened?

Lately, probably the last three or four months, it is sometimes days before I pick up my next book.  It's not that I feel like I'm in a slump, I've enjoyed the books I've read.  I loved, The Demonologist and The Flying Troutmans.  Blue Lily, Lily Blue and Specials had me riveted.  Why did it take me so long to pick each of those books? There were days between all of them.  I could have read another (short) book in the time it took me to pick something.  Is it because I have Emily Dickinson's collection on the go?  Usually, I only have one "currently reading" book at a time, but I started her poems months and am taking my time. The poetry is an ebook, so if I'm out, without space for my novel, I can take in a few poems.  I also find by spacing them out, I'm enjoying each poem more. (I'm taking lots of notes too.)  However, I don't think that's it.  I've been reading the poems for about eight months now and this change is newer than that. 

So, what is it?  Why am I now leaving so much space between books?  How long do you let go by before you pick up another book?

It's been two days since I finished my last book.