The amount of time a 15-year-old should spend on homework depends on the student's individual needs and abilities. Generally, it is recommended that students in this age group spend between 1-3 hours per night completing their assignments. This includes both school work and any additional studying or research needed to complete projects. It is important for parents to monitor their child’s workload and ensure they are not overburdened with too much work or feeling overwhelmed by the amount of homework assigned. Additionally, it is essential for teens to have adequate breaks throughout the day so they can remain focused and productive while completing their tasks.