You may want to reconsider when you read. When reading non-fiction, I find reading for just enough time to get a clear idea of a concept that is being described to me allows for better integration and aha! moments during the day. So, I find it beneficial to read them when my life is busy.

The fiction books seem to be needed, for me, to not exhaust myself on non-fiction. The best time for me to read these is when I am less busy and have down time.