On my side my maternal grandparents' fathers both fought in WW1 and were lucky enough to return home alive, although my grandfather's father died a horrible death not too many years later as a consequence of having been gassed in the trenches. When I joined the Army myself my grandfather gave me his father's medals, papers and the chocolate tin that had been sent to the soldiers at Christmas containing a small signed copy of St John's gospel too.
I know very little about my Grandmother's father's service as she dislikes talking of war, although I do have a photograph of him on his horse on uniform.
During WW2 my maternal Grandmother's brothers fought, all but one died. I know no other details as my Grandmother will not mention the war. Ever. My maternal Grandfather fought, took part in the D Day landings and then was almost killed not long afterwards, having been shot in the head - he survived but was left with one eye and disfigured but returned to Germany and was involved in the liberation of a labour camp (the exact location of which went on to become a British Forces base and where I was posted during my own career for a few years); he wanted to remain in the Army but was medically discharged a few years after the war had ended as his health deteriorated a little. He didn't mention the war until I was a teenager, mostly as it upset my Grandmother so much; he wasn't even "allowed" to watch war films. In later years he talked to me a great deal about his experiences when my Grandmother wasn't present and even, not too long before his death, wanted to attend a Remembrance Day parade. I took him and marched with him, I looked across at him in the church and tears were silently rolling down his face.
My paternal Grandfather was an engineer and also fairly old by "fighting" standards so did not fight in WW2 - he contributed to engineering advances of equipment but remained a civilian.
I myself joined the Army and, when I did, my Grandpa gave me his medals, capbage, sgein dubh and lots and lots of photographs, a uniform epaulette and much more service - related bits and pieces along with his own father's medals and service related belongings. They are my most treasured possessions. My Grandpa also attended my passing - out parade. I completed several tours in Iraq and in Afghanistan.
My husbands' maternal and paternal sides' great grandfathers all served in WW1, his grandfathers both in WW2 (RAF), his father served a full RAF career and my husband himself is still serving in the Army.
My stepdaughter's husband is a serving member of the RAF.
I was thinking today how incredibly lucky both our families were (bar my Grandmother losing her brothers) in that all who fought had returned home - a very rare thing, especially as most were involved in some of the major battles of the wars. The mental impact of the experiences however just cannot be underestimated.