Willpower: when to work it, when to rest?

When I started reading Willpower: Rediscovering the Greatest Human Strength, by Roy Baumeister and John Tierney, I was confused at first.  The first few chapters talked about how all people get drained if, over an extended period, they exercise willpower or make many decisions.  Baumeister was one of the top researchers in this field of psychology and coined the term "ego depletion" to describe how we increasingly lose our ability to push ourselves, to resist temptation, to make good decisions, if we make too many decisions or push our willpower too long in one sitting.  He describes judges from Israel who heard prisoners plead for parole all day long.  Early in the morning, the judges were fresh.  They granted parole, on average, 65% of the time.  But granting parole is a risk.  What if the felon repeats the crime?  By late afternoon, the judges found it easier to play it safe.  They granted parole just 10% of the time.

What confused me is this:  are the author suggesting that we avoid making decisions?  Should we avoid pushing ourselves?  Should we avoid doing anything difficult because, as the authors say, we have a limited amount of willpower to use for all the tasks and decisions in the day?  Should I just go for the easy way all day long so that I've conserved my willpower for emergencies?

The answer is both yes and no. 

• Yes, I should conserve willpower.  It helps to be aware that willpower and good decision making are both limited resources.  Best to not waste them on things we don't really value.  An example for me is driving in the center lane of the highway so that I don't need to make decisions about letting faster cars pass me or whether to speed up or slow down so that cars entering the highway can merge.  Better to stay fresh for tough decisions at work or at home in which it matters to me to be at my best.
• But, no, I should also exercise willpower.  Later in the book, the authors describe "Willpower Workouts".  Research shows that willpower can be strengthened if you take on just 1 or 2 things at a time that require willpower.  For example, students in a study who were told to stand up straight or sit up straight whenever they thought about it ended up with improved willpower in all areas of their lives versus a control group.  Without being told to do so, they ended up studying more, exercising more,  amd eating better.

So the bottom line is, don't make 20 New Year's Resolutions because that isn't realistic for almost anybody.  And, yes, don't make trivial things like driving too complicated and draining because you are better off saving your limited willpower for things that matter more.  But it is always a good idea to have SOMETHING, some part of your life that you are pushing yourself to change.