I have a serial cardigan abandoner. He'll run out then come home with a job lot that have been peeled off the cloakroom floor.
In y1, I ended up numbering them so I could trace them better as I knew I was looking for cardigan#2.
I've gone sloppy about the sew in labels, but I do make sure I've written it in. As a brownie leader, I know the trauma of matching owners to 30 identical tops in a range of 3 size variations.