There are two types of custody which are physical custody and legal custody.  Physical custody refers to where the children are living.  If one parent is awarded physical custody, that means the children are living with that parent. Legal custody means making decisions about the children such as their education, health care, etc.  In this case both parents have been awarded legal custody which is what is meant by joint custody.The court makes decisions on custody based on what is considered to be the best interests of the child/children.  If there are changed circumstances in the future, it is possible that custody could be modified.  However, courts are reluctant to modify physical custody because it is too disruptive for the child to be removed from the home of the parent where the child is accustomed to living.