It is not a waste to buy arch support for your child but you can hold the idea for some time if your child has no specific foot condition. A child’s feet grow and change rapidly compared to an adult’s feet. To assess, check out for cues like how your child walks or runs or if he complains of any pain or gets fatigued easily, look for the arches if it’s flat or high. However, it is better to consult a podiatrist or a pediatrician for a proper assessment.