After placing the right people in the right spots, we have to make critical decisions about which tasks to do ourselves and which to accomplish through those individuals. Naturally, there are certain tasks we never delegate. Peter Drucker refers to those as a leader's "unique contribution," what he alone brings to the organization. Leaders shouldn't delegate what they are best positioned and gifted to accomplish.
A senior pastor, for instance, typically is gifted and trained as a teacher. Often his most significant contribution is teaching on Sunday mornings. So when he gets overloaded, he should focus on message preparation and delegate competing tasks to others.
My unique contribution at Willow Creek is to build our sub-ministries. No one else is so commissioned to help our ministry directors develop their departments. Someone else can type my correspondence, lead singles meetings, or administrate our magazine, but no one else is called particularly to oversee our department leaders.