No, not anything in particular.  It's mostly natural because if I spend too much time in the "just work hard" extreme I get burned out eventually.  I'm also too antsy to spend a lot of time in the learning extreme because I like to see concrete results eventually.  Since I'm comfortable with my long-run track record of learning and producing, I never let myself feel guilty for doing either extreme.<p>The only other factor is time of year.  I tend to learn during Christmas because when I was in college I used that time for reading and reflecting between semesters.  I still get the urge to just sit and read and explore around that time of year.