Missionaries are made to come and go, or at least they should be. Jesus had about three years of ministry and then he left. The Apostle Paul went from town to town. There’s a bifurcation in modern Western missions between missions lasting two weeks and those lasting 20 years or longer. I worked with situations where a Western missionary has worked in the same language for 20, 30 or even 40 years. Sometimes my American friends express admiration for missionaries who spend many decades in the same place, but I’m pretty sure that is not always a good thing.
A missionary’s role should change as he or she trains local people with whom they are in ministry and they take on more responsibility. We see this in the ministry of the Apostle Paul. After announcing the Good News and seeing some converts, he named and mentored leaders for the new Christians before going on to the next place. He then kept in contact, prayed for those he left and visited them when that was possible. Leaving did not break his relationships. Another aspect of Paul leaving well was that he incorporated some of the new believers from the place he was leaving in his mission to the next place. He also brought all of them into praying for it.
We shouldn’t follow Paul’s example slavishly, but we ignore it at our peril. Depending on the type of ministry (translation develops slowly), a missionary might stay in one place for a long time. But even a long stay should be preparing for a good departure. Bible translation not infrequently takes place where there are low levels of education, making it difficult to train local people in all the complexities of translation. But difficult does not always mean impossible, especially when the time frame is 20, 30 or even 40 years.
A while back, a missionary told me that another missionary should be allowed to stay where they were because that had become home. Being in a place that feels like home is a good thing, but it is not a valid missionary goal. In fact, it sounds like a way to justify staying long after one’s missionary goals have been accomplished. Missionaries who stay in one place for a long time may do so because they like it, they are comfortable, or because they get respect. Recent research found that 96% of missionaries reported that they were functioning well in the society where they are conducting missionary work. Moving would disrupt that. A few times in my career, missionaries faced with a potential change of location have said to me that they want to stay put because “God has called me here”. In every case, that “here” was a situation that they found personally fulfilling.

Dayle and I with Abidjan staff a few days before our departure. They gave us traditional Yacouba outfits.
I recently took an interim assignment in Côte d’Ivoire. I was given a very specific six-month mandate – take care of current matters and work with a national committee to recruit an Ivorian director. When those things were done, Dayle and I returned to our assignments in Ghana. We had an advantage. Our assignment specifically demanded a transition. We had no choice. Perhaps all missionary assignments should be like that.