At 92, Queen Elizabeth still looks as healthy as ever. As a full-time member of the monarchy, she can still host diplomats and government leaders from around the world, attend royal engagements and travel for long hours to perform her royal duties. But until when? If the Queen is already too old and sickly to reign, can she retire from her current position to hand over the crown to his son?

One royal succession rule states that it is possible for Queen Elizabeth to retire from her royal duties, but it is not exactly considered retirement. This royal succession rule suggests that the Queen cannot totally retire from her royal duties unless she chooses to abdicate. While she can slow down on her royal responsibilities when her health becomes a concern, she cannot just stop being a Queen without abdication.

If the time comes that Queen Elizabeth is already too old or sick to perform her duties, then a regent will step in to perform her duties on her behalf. In the case of Queen Elizabeth, the regent will have to be his son, Prince Charles, who is the heir to the throne.

If the Queen becomes too weak to carry out her responsibilities in the monarchy but does not abdicate, she can appoint a regent as a placeholder. That means that Prince Charles will have to carry on with the Queen’s duties until she ultimately dies and he becomes the new king.

A regent also serves as a placeholder if a king or queen is too young to perform his or her royal duties. By royal rule, one cannot ascend the throne until he or she reaches the age of 18. That means if Prince Charles and Prince William suddenly die, Prince George, who is the next in line to the throne, will be king. But since he’s too young to reign, his uncle, Prince Harry, will be the regent and act as king until his 18th birthday.

As of now, Queen Elizabeth is still in the pink of her health. A quick look at her diary will reveal how busy she still is regardless of her age, doing a lot of travels to perform her royal responsibilities. Her royal outings show that despite her age, the Queen is still physically fit and mentally alert to even consider abdication, so it looks like Prince Charles will have to wait for many more years before he takes the place of his mother.

Queen Elizabeth Britain's Queen Elizabeth II (C) speaks with Australian Prime Minister Julia Gillard (L) at a banquet dinner during the Commonwealth Heads of Government Meeting (CHOGM) in Perth on October 28, 2011. RON D'RAINE/AFP/Getty Images