Generally it's cheap junk. Like if you are cold, buy a cheap sweatshirt for $5 or $10. When it gets annoying to carry it, and you haven't worn it lately, leave it behind. If it gets stolen from the laundry, who cares.

This is in contrast to buying a $100 Patagonia super-awesome lightweight shell, that is certainly better than that cheap sweatshirt, but that you need to treat as a prized possession and carry everywhere.

Well ideally, you'd buy it because it's something you can't live without, so you'd bring it with you, and leave some extra space in your bag for such things, or jettison something which you deem less valuable.