When a church loses its pastor, all kinds of things go topsy turvy. More often than not, the pastor leaves due to crisis. His departure is bound to upset a good number of the congregation if he leaves on bad terms. Typically, the Board of Deacons makes sure the church gets pulpit supply. Sometimes this is erratic, often with late Sunday night calls of desperation to find someone. Often, the pulpit supply is good, at other times, maybe not. A major problem is that the Deacons finally find someone willing to come on a regular basis. But then, this preacher gets into his head that maybe he should become pastor. He starts building up loyalties in the congregation. In effect, this circumvents the legitimate pastoral search. It becomes a runaway enterprise which the pastoral search committee can't control. Meanwhile, the church has not had a chance to recoup or heal from its recent loss. Ultimately, the church will likely hire the interim minister, but because the prior problems have not been resolved, the new pastor loses it in another 1-3 years. The cycle repeats itself.
A programmatic Interim Ministry fixes this problem. Some denominations facilitate this process. When the church declares a vacancy, it can appeal to the denominational structure to send it an interim minister. This interim minister is specifically trained to deal with the oddities and demands of interim ministry. He is employed by the denominational agency and is subcontracted out to the church. He serves as long as the denominational agency and the church mutually consent. One of the commitments made by the interim minister is not to candidate for the pastorate of his interim ministry. This is a huge bonus. It allows him to do the things he really needs to do without becoming conflicted by an interest in getting the job. Actually, the interim minister who knows that he cannot be considered for the pastorate can spend his capital on fixing any dysfunctionalities of a church without worrying about his job security. Everyone knows he is a short termer (perhaps 1-3 years), and is willing to give him some slack. They also realize he is not doing this or that for his own gain, but out of his professional concern for the church. The "dedicated" interim minister is, in effect, an outside consultant who becomes intricately connected to the church. Many churches are like dysfunctional families. Dysfunction is passed on from generation to generation until someone breaks the cycle. The specially trained interim minister works on breaking this cycle.
Fortunately, you don't have to re-invent the wheel. Specialists have studied interim ministries and have outlined a program for interim ministry.