JOEL - New mission presidents along with their wives are assigned and set apart by the First Presidency of the Church and normally serve for a period of about 3 years. Couples who are considered for these positions are members in good standing with a long history of experience and leadership positions in the church. They will have probably already served a full-time mission when they were younger. They do not ask to be called as a mission president but are always willing to do it if the call comes to them from Church leaders.
Quite often they are retired couples, but can also include younger couples with children, whose professional employment is interupted. Whatever financial losses they accrue are part of the expected sacrifice. The family involved gives of its time and energies without salary, though there is a modest allowance for living expenses. The mission president oversees and directs the missionary activities of a few hundred missionaries in a particular region(mission) in the world. There are over 340 missions in the world today with over 60,000 missionaries serving in over 140 nations.