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The second part of my question is, if neither my ex-wife or my son seem too concerned about school work and he either flunks or ends up going to HS for a 5th year - how long do I have to keep paying child support? I understand if an accident or illness or other unforeseen event resulted in a delay in graduation that it would be appropriate to continue to pay child support for another year, but due to the attendance issues and just not trying, it doesnt seem right. Especially when the $ never really goes towards providing a stable environment (several evictions and foreclosure). Interestingly, my ex dropped out of HS after freshman year. Our order includes the standard til 18 or graduates whichever comes last.
There is no age cut off for when judges will or will not modify custody. The court is focused on the best interests of the child and recognizes that things can change over time, which warrant a change in custody, no matter the age of the child.
You must pay child support until the child is 18, or if he is still in high school making progress towards graduation, until he is 20.