End of assignment: this is one of the most common reasons for repatriation to occur. If your visa to work in a particular country is linked to your role, you may not have much choice but to return home.
Missing family and friends: this is a motivating factor for many expats who have been abroad for a long period to return home. No matter how settled they may be in their home away from home, the support of family and good friends is difficult to replicate. This is particularly true if you decide to start a family while abroad. You may want your children to grow up near grandparents or other relations.
Language barriers: living as an expat may have been easy while working on assignment in your native language but what happens then? If you are not fluent in the local language it might be challenging to move from your existing role to another role in your expat destination.
Health concerns: if you have access to universal healthcare in your home country then health concerns might be a reason to return home. It is important to research carefully if you are returning home for this reason because you may not automatically qualify for healthcare immediately.
Better prospects: finally, if you and your family believe your career prospects are better in your home country this might spark a desire to return home.