Change in Payor’s Ability to Pay: The financial ability of the party ordered to provide support is an essential consideration in the determination of whether there has been a substantial change in the parties’ financial circumstances. The paying party must have the financial ability to provide for those needs before a court can order an increase in child support payments, regardless of any increased need for child support. Voluntary changes affecting the ability to pay, such as remarriage, the purchase of a new residence, or job change, will not support a reduction in the amount of child support. 

Change in Ability to Contribute to Child Support: An increase in the income is a factor to be considered in a proceeding to modify a child support order. A substantial increase income may justify a change of schild upport payments.

Child’s Attainment of Majority: Generally, an obligation to provide child support exist only until the child reaches the age of majority. A court may order child support for a high school student between 18 & 19 years of age, if he or she has a reasonable expectation of graduation before the age of 19. Such extended support is inappropriate if it appears that the child will turn 19 before graduating.

Emancipation of Minor Child: An obligation to support a minor may be terminated by the court before the child reaches majority if the child has become self-supporting or has become emancipated. “Emancipation” may occur through  marriage, enlistment in the military or the establishment of a home away from the parents.

Income of Child: Income earned through a child's employment does not decrease the child's needs nor justify a reduction in child support. Income earned by the child from sources other than employment, however, may be taken into account when determining the child support.

Support of Subsequent Children: A payor's obligation to support children from a subsequent marriage may not be the basis for decreasing support to the children of a prior marriage. In Robinson v. Robinson, 657 So 2d 958,960 (Fla. 1st DCA 1995), the court found it to be "a legislative recognition that the parties should be aware of their support obligation to existing children, and should take that into account prior to assuming further obligation".

In exceptional circumstances, the court may consider the subsequent child's need in setting child support. In Gebauer v. State, Dept. of Revenue ex rel. Hurburt, the severe illness of the mother's subsequent child, forcing her to quit work and stay home to care for the child, was found to justify a downward modification on her prior child support obligation.