When should a parent coordinator be used?

A parent coordinator is a neutral third person who is appointed by the court to resolve custody disputes between parents who no longer live together or are divorced. Resolving disputes by a parent coordinator is less expensive than court proceedings and much faster. Either party can "appeal" the decision of the coordinator to a Judge.
A parent coordinator is appointed by a Judge and the order will spell out the specific powers of the PC.  The cost of the parent coordinator is usually split between the parties and the PC process is usually conducted without involvement of attorneys.
A parent coordinator works best when both parties act in good faith. By the time a family becomes involved with a PC, the two parents have developed a history of not working together. In the worst cases, they are frequent users of probate court as they return to have the judge decide minor matters. Often, they tend to oppose each other in parenting decisions and have difficulty compromising. While they both may seek the best interests of the child, they are not interested in reaching an agreement with each other. In many cases, neither parent’s position is harmful to the child. However, the parents simply won’t agree with each other. In cases like this, the decision of the PC is not nearly as important as the fact that a decision is being made.
Each person who acts as a parent coordinator uses different procedures. A typical method is for the PC to meet the parties to get to know them. After that, contact is usually through email or telephone calls. Sometimes, the PC will request a meeting with the two parents to resolve matters. Frequently each parent will email their decision to the PC and the PC will email a decision back. This keeps the cost to a minimum.