I find that interesting, because I always wash winter hats after a week or two of wear. I might not feel compelled to wash a wool sweater that often, since I would be wearing a turtleneck or other shirt under it and it wouldn't be touching my skin directly. But a hat that will be right against my skin and hair, and be soaking up sweat, skin oils, hair spray and maybe some makeup, I wouldn't want to keep wearing over and over without washing it. It might be another case of knowing your audience and finding out if the intended recipient goes all winter wearing the same hat without washing it, or if they prefer to wash them more often.