I definitely take breaks with most books. If its a long book that's requires me to pay strict attention, like with Lord of the Rings, I usually have another book I'm reading to take breaks from the intense book. The other book is generally a YA or romance that is an easy read.
For example, my currently reading list from GoodReads looks like this:
- The Two Towers by JRR Tolkien
- Twilight by Stephenie Meyer
- The Killer Angels by Michael Shaara
- New Orleans Ghosts, Voodoo, and Vampires by Kalila Katherina Smith
Each of these books serving a different purpose. Two Towers is my intense read, Twilight is my fluffy YA re-read, The Killer Angels is my current audiobook, and the New Orleans books is spooky, so I can't read it all the way through without taking a break so I don't start seeing ghosts in my apartment.
Which book I pick depends on what mood I'm in and what I want to do with my evening. LotR and Twilight are on the Kindle, so I might go with one of those if I want to knit while I read. Killer Angels is also good for when I want to knit or if I'm in the car for a while. The Ghosts book is great if I'm watching tv, since the television will distract me just enough to keep me from getting too spooked.
The usual exceptions to the "multiple books at one time" thing is a new release by a favorite author. If Sherrilyn Kenyon, Jr Ward or Richelle Mead have a new book out, chances are that I'll read nothing else til I've finished it. Usually, these are series books where I'm anxious to see what happens next!
All in all, having multiple books going works for me! Its also one of the things I love about having a Kindle: multiple books, one device, no losing my place!