Older people sometimes go on missions after their children grow up. They get to go with their spouse. There are many different kinds of missions for "senior missionaries". Some of them are only a few months, and some of them are a few years. These missions can be "service missions", which means that they go to help people who live in the area. Sometimes the senior missionary is a "mission president". This means that they lead and help young missionaries in the place where they go to live.