Being a good leader requires not only a myriad of solid skills, but more importantly, good judgment and the discipline to focus on the most important activities at any given time. One of the best coaching messages I have ever received as a leader was to focus my activities on the things that only I could do, allowing others to do the things for which they were best suited.
It sounds simple, but why is this so important? The simple answer is that if you don't, you won't be leveraging the total strength of yourself or your team, nor will you be challenging your team members to grow by giving them more difficult but rewarding work. Effectiveness as a leader really boils down to how well you prepare your team to execute. Identifying the strengths and weaknesses of every member of the team and utilizing this assessment to maximize efficiency and quality of work is the leader's charter. This includes assessing your own strengths and weaknesses. From there, you set the overall priorities and assign roles on the team based on your assessments. This allows your team to operate at maximum effectiveness, no longer limited by your personal bandwidth as the leader!
That seems pretty straight-forward,right? But why is it so hard to do? For starters, new leaders are often given the opportunity to lead based on their performance as individual contributors, where they have been charged with completing many tasks, some of which are not necessarily in their areas of strength. So naturally, in their new leadership position, they continue executing, regardless of what is asked of them. The concept of delegating or balancing work with their colleagues is probably not commonplace yet in their career at this level. It is a behavior that must be learned and in some company cultures it can be more challenging to learn than in others.
Another truly practical reason is that the team the leader is working with may not be well equipped with all of the necessary skill sets to accomplish their mission, leaving tasks not particularly well suited to the leader on his or her desk to complete anyway. This is a problem that must be solved organizationally, either by training of existing team members, or changing the team composition.
But the most likely culprit for leaders not being successful in focusing on doing the things only they can do, is they lack the discipline to prioritize their activity in this manner. I recognize the difficulty in doing what I am advocating here. In the short-term, it is often easier and more expedient to complete a task yourself, rather than ask one of your team members to complete the task and trust them to do it in a manner acceptable to you. But if you don't, you'll be committing yourself to completing that task forever! Worse than that, you won't be challenging your team to grow nor giving them an environment that cultivates a fulfilling career for them.
Good coaching from superiors in your organization or outside coaching resources can often help you understand your areas of strength and weakness and can help you to develop a default prioritization for your activities. Your coach can also help you understand your team's abilities and how to maximize their performance once you've given them assignments for which they are best suited. The bottom line is...don't go it alone! Seek help in understanding your own strengths and weaknesses and in holding yourself accountable to focusing on doing the things that only you can do!