I don't keep them and have never kept them. The only possible use that I would see for chatlogs in the first place is capturing those wonderful MysteriousWanderer quotes that pop up every now and then, but since everyone else was logging IRC chats, this didn't prove to be necessary after all. I format my computer and move around too much to keep those sort of things lying around somewhere anyways. And I'm not going to make like a CHATLOG BACKUP or something, because that's just fucking stupid.