Mediation is when a neutral party attempts to assist the parties in coming to an agreement. The mediator can not issue any legally binding agreement, but rather guides the parents and offers suggestions. If an agreement can not be reached during mediation, the process is then moved to litigation within the court system. Courts take child custody issues very seriously, as they will very heavily impact the rest of the child's life. Many, many factors are considered when determining the best arrangement, including the age of the child, which parent is best able to provide adequate shelter, food, and basic necessities, the stability of each parent, and it the child is older than age 12, the wishes of the child.
Parents can modify the arrangement if both are in agreement as to the change.
However, if one parent disagrees with the proposed change, the other must file a motion in order for the courts to consider the modification. Ideally, it is best if your child can spend a significant amount of time with each parent, and both parents are on amicable terms with excellent lines of communication. But. . . . . we don't always live in an ideal world. Sometimes what you know about your partner that makes he or she unfit as a parent is often unknown to the ideal world. However, be careful not to alienate your child from the other parent unless absolutely necessary, as it is truly beneficial to a child to have the love and support of a mother and a father.