In the early days of the church, missionaries left their wives and children, often under difficult circumstances, to answer the call.
Missionaries still leave family and friends, but also education, sports and other significant circumstances in their lives.
They must also box up their favorite electronic devices, turn off the cell phone, log off their Facebook account and put away the computer and video games.
This is harder for some than one might think, says former LDS mission president Brad Wilcox.
"I started sensing that it was an issue early on (as a mission president) and it has gotten worse and worse. We definitely saw it as a concern in the mission and it concerns me as I see young men getting ready for missions," said Wilcox, who presided over the Chile Santiago East Mission from 2003 to 2006.
Wilcox is aware of missionaries in the MTC and field who he says are literally suffering withdrawals from cell phones, social networking and video games as if they were drugs.