If it has been less than three years since the child support order was put in place, Florida requires those requesting a post-judgment child support modification to show a significant change in their financial circumstances that would result in a difference of at least 15 percent of the amount of the payments owed. After three years, the petitioner must only show that the circumstances would result in a difference of at least 10 percent—or $25—of the ordered amount.
You must also be able to show that this change in circumstances is permanent by proving that the change has lasted for at least six months. You must also show that the change was involuntary, meaning it came from circumstances beyond the petitioner's control—such as the petitioner suffered an extended illness or they were laid off from their job. Quitting a job or taking a lower-paying job are considered to be voluntary actions.