After a divorce, courts frequently entertain motions to modify the divorce decree. Modification leaves the general purpose of court order intact but amends the details. One cannot move to eliminate child support, but a custodial parent can appeal to change the amount due to a change in circumstances. The phrase change in circumstances controls the logic of such modifications.

Very often the custodial mother asks the court to increase child support payments because of increases in the cost of living. Because of this, some separation agreements provide automatic escalator clauses that eliminate the need for court-ordered, post divorce modification.

In considering modification of child support or custody orders (and this includes the terms and conditions of visitation), judges are guided by the best interest of the child. For example, if two former spouses cannot make their custody and visitation routine work, courts will order a change based on the idea that a continuing relationship with both parents is in the best interest of the child. Courts entertain motions to modify when the custodial parent interferes with rights of the noncustodial parent. Courts sometimes modify custody and visitation orders when one spouse (very often the wife) wants to relocate beyond an easy commute (generally 150 miles).

In the modification of alimony, state statutes mandate many factors that courts must consider. However, in general, courts consider modification of alimony based on the overall situation of the payor, who is usually the former husband, and the overall situation of the payee, who is usually the former wife. Of the four categories of alimony -- limited duration or term, rehabilitative, reimbursement and permanent alimony -- courts most frequently hear motions to modify permanent alimony.