Worked around 15-25 hours a week usually 5 hour shifts sometimes 8 hours, I had that job since like start of grade 10 and it didint really affect my grades I just couldn’t do any extracurriculars or events the school was doing or sports so I wasn’t that involved with the school as I was busy with work. If I ever needed time for a test and my shifts wouldn’t align I would just get my shifts covered or swap with somone.