I am not a vet, so my knowledge on this is limited at best-yet...

It is my understanding that active American armed forces get 30 days vacation time annually, including 10 days before stateside assignment and 15 days before overseas assignment.

This differs substantially from missionary vacation time, which, at my understanding consists of a 10 minute phone call(undoubtedly a collect call) on Mother's Day and Christmas.

One must wonder if the missionaries were able to come ho,e for a month,annually, during their service, would ANY of them ever return?

I would suggest not.

And

You get paid for any leave you don't take up to 60 days when you muster out.

Imagine getting back two months of expenses at the ebd of your mission.

You never get any vacation while on your mission. The best phone calls were with friends from home while they were also on their missions at the same time I was on my mission. One of them was copying random names of supposed investigators out of the public phone book, in to their reports to the mission president as a means of staying out of trouble. One of them got in to trouble after getting a sunburn on his face in the shape of ski goggles. Lots of laughs with close friends who were living under some different, some similar restrictive rules I was living under.