One of my all time favorite quotes comes from Jim Collins' book Good to Great. It reads as follows: "The moment you feel the need to tightly manage someone, you've made a hiring mistake. The best people don't need to be managed. Guided, taught, led - yes. But not tightly managed."
As leaders of any organization our time is precious. We simply do not have enough time to micromanage employees who are not meeting the minimum requirements of the job. Of course every employee will need a little guidance and coaching, but if your organization utilizes rigorous hiring practices and has high expectations for employees you should be able to, "Hire good people and leave them alone." (from Daniel Pink's Drive)
Don't get me wrong, clarifying job responsibilities and expectations is a hugely important role for the leader (I actually developed a three page Expectations and Responsibilities manual for our administrators). However, once expectations have been established if a leader realizes they are spending time constantly revisiting expectations for an employee and - worse yet - find themselves having to further clarify those expectations, there is a very good chance that the employee should not have been hired in the first place.