When I was going to on the mission field, Mission to the World (MTW) required me (and all the missionaries going on the field at the time) to go through a pre-field training. It was a really great experience. I learned about language learning, adapting to being on the field, learning to be a learner, and many other important issues for life as missionary. The one topic that was mentioned, though not discussed in depth, was cultural fatigue or in some cases, homesickness. This portion of the training has stuck with me, and I am regularly reminded of it.