I wonder if Mrs. Weasley puts special charms and things on the sweaters she knits to fit each of the kids?
Like, a tear-resistant and fire-proof spell on Charlie’s because he always gets holes in his clothes. An ink-resistant charm for Percy because he sometimes knocks over his ink well when he gets really into his writings. A self-cleaning one on Fred and George’s because she can’t trust them to do laundry. You know, just little things like that, because even if they don’t wear the sweaters often Molly wants to make sure they’re perfect every time they do