How Do You Translate Unknown Concepts?

I have seen an increase in missionaries coming to the field for a fixed term. That is to say, they come to the field with a particular term length in mind. Some will come for two, four, five, or ten years. Then, they return to their home country. From my experience, this seems to be the norm now. And when we talk to Americans, they usually ask us how long we are planning on staying. I will respond with, “our plan is to die in Cameroon (hopefully later rather than sooner).”