What did people have to leave behind when going to World War I and 2?

The men who enlisted in the army in World War 1 and 2 were very young men. The new recruits were most often 18 and 19 year old boys essentially. So most of the time they were leaving behind a family, mother, father, siblings, maybe even a girlfriend, but the majority of the time there was not much value left behind. This is why the WW1 generation is sometimes called "The Lost" Generation because really they were not very economically fortunate and so a large majority of the male population left to fight in the war in hope that they would achieve glory and honor.