Scripture Reference: 

Acts 20:28
"Keep watch over yourselves and all the flock of which the Holy Spirit has made you overseers. Be Shepherds of the church of God, which He bought with His own blood."

Ecclesiastes 3:1
There is a time for everything, and a season for every activity under heaven.

The Experiencing God Through Missions Inc Board of Directors does not serve specific 'term limits.' Their 'season' is as long as they are empowered by God to serve and  are physically and mentally capable.