what happens to a guardian angel when it's subject dies?

Well if the person dies of old age after a good long life the angel gets re assigned an new person

If the person gets horribly mutilated in a terrifying accident involving a fork, some springs and a pencil sharpener then the angel has his suitability for the position reviewed.

The way it works is that certain spirit or angel guides are assigned to us at various stages of our lives. There is usually one main protector and then sometimes others to guide or guard us during certain stages. Each has their own specialty. Often times these spirits are people who have died and are sent to do this to make up for something they did while they were alive, or maybe because that person possessed a certain talent in life that they now need to help someone else develop.

So this goes on through a person's whole life. Sometimes these guardians and guides appear in dreams, whisper inspiration into the person's ear, so to speak. Then when the stage they are meant to guide that person through is done, they are either reassigned if they need to help someone else, or they graduate further in the afterlife. The same goes for your guardian angel. When the person they are guarding dies, they are either given a new assignment or they graduate further up the hierarchyy of angels.

And that's the best advice I can give.

Angels do not age or die. Their minds are so immense they can deal with millions or even billions of people at one time. So, we probably share guardian angels. Their job is to protect the freedom of our soul's choices, not to keep us alive and unharmed forever. Some people get direct intervention by angels for various reasons. One being that their soul pupose in this life has not been fulfilled and they need to live a little longer. The other is that a great saint of God is praying for them and has the mental talent to bring angels in time of trouble.

First the angel takes the person to heaven and give them the reassurance they need for this big change, then my guess is that they become a guardian angel of some new Christian, but this isn't told in the Bible.

Retirement with full pension plan and benefits. =)

Angel's WHERE created. They get assigned as guardian angel. They might get different duties, but probably just get reassigned.

Angels from Islamic prospectives are like a Allah's army. The one in Q, will be doing its duty continuously,and that could be other people who are just born when we expired.

There is no such thing as a guardian angel. Stop living in a fantasy world.

Hits a bucket of balls in Florida

it moves to florida.