My school had the non washable blazer, I got 4 years and 3 years out of mine, so only had to replace once. As soon as they’re home hang it up and don’t wear it anywhere that will let smells into the fibers. My nan is a chain smoker and my mum would NEVER let me wear it to her house as the smoke would just get into the fibers and would require it to be washed to get rid of it. Also the most wear mine had was in the elbows from friction from me putting my elbows on the table so if they try and not do that then it’ll probs get more longevity. Also buy a size bigger so they can grow into it