I jotted down these thoughts on ministry some time ago while reflecting on the grind that parish ministry brings to a pastor. Flawed, brief thoughts, but I think there is some truth here.
Leadership of the church is like a hospital medical staff. The pastor is the head surgeon. Elders are doctoral interns, able to do medical acts. Deacons are nurses. Much of the time, we aren’t doing routine checkups twice a year on people. Rather, we are like a hospital in downtown Chicago on a Friday night receiving patients with gun shot wounds. Ministry is not routinistic, but occasionalistic.
Obviously I am presupposing a “three-office” perspective concerning church officers over the popular two-office or two-and-a-half office views. Still, I think there is much to meditate on with these words. Maybe a future blog post will explicate this more.
O Felix Culpa 
Ministry is both rountinistic and opportunistic. Public ministry is quite routine. You labor week in and week out, faithfully being consistent in the ministry of the Word through preaching, teaching, praying etc.
But private ministry is opportunitistic- suited to crisis, applying the Word in counseling & prayer for the specific needs of the persons involved.
A healthy ministry has both public and private ministry; routine and opportunistic.
Keep thinking these things through. Most people don’t.
I am glad you brought up this point since I did think about this and plan to explicate this more in a future blog post.
The public ministry of the church is bound to the ordinary means of grace (ministry of Word, sacrament, prayer) along with other activities (mercy ministry, outreach, etc). While the routinistic element is present in these means it is also important to remember the Calvinian perspective that these means are not effectual unless embraced by faith. And it seems hard to have the ministry of Word, sacrament, and prayer to be embraced by faith without the preacher working hard to contextualize his public ministry in terms of what his congregation needs to hear/see/do. I know some Reformed folk who treat the ordinary means of grace as the “only” means of grace and thereby under-contextualize to the extent that their ministry is more, dare I say, Roman Catholic with an ex opere operato view than the Calvinian/Reformational “offer-reception” model.
Now, obviously the occasionalism of private ministry is different from public ministry. And there is even a routinistic element in private ministry as there is in public ministry (prayer, Scripture). So perhaps a balance between routine and occasion is needed. Though even with the medical imagery I give it is implicit that the surgeon employs basic, routine elements in his surgery of people.
You always think a D.Min thesis would be easy. But sometimes there is as much precision needed in practical theology as there is in systematic theology.
Blessings to you and your family, Steve.