For many ministry leaders, and even other leaders (you can replace the word ministry for leadership in these questions) we forget that a core requirement of leadership is life-long learning. The truth is that we always have more to learn, can always grow and will always have strengths and weaknesses to develop and address. The world also continues to change as does each of the areas, fields and organizations/ministries that we serve. We must continue to learn about our own leadership area if we want to continue to be effective.
Our learning, however must not be limited to our area of responsibility or expertise. While that may be the focus of our work and learning, we must not focus all of our learning in one area. In fact, great leaders know and learn about areas outside of their area of expertise while allowing those areas to have their own experts. For example, as a Pastor I might learn a lot about healthcare and medicine as I work with the sick an the dying. This does not make me a medical doctor, but it can make me more effective in working with people in their illnesses and in interacting with medical professionals.