I sometimes encounter that same issue - the question of whether to keep entering after winning (not an issue this time ^_^). My personal balance is to take a week's break from the contest and only participate in voting for others. But different people will use different methods.
I do not tend to go for book reviews but the psychology and power balance of individuals and peoples -and vested interests - made for interesting reading. I'll decide a little later this week whether this has my second vote as its early days - but well done on the review. :c)