In the 70's and early 80's the suits that Mr Mac sold would only last for about 18 months. It was getting very expensive for missionaries to have to purchase new suits near the end of their missions and many missionaries were just continuing to wear the old ratty looking suits and giving TSCC a bad image. The inspired answer to the problem was to shorten the missions to 18 months. A few years later Mr. Mac improved the quality of their suits so they would last 24 months and they leaders decided to return the mission length to 24 months so they could get full value out of the suits.