I don't really understand why this is worth thinking about. It's not like I can't have people over to my house 'cos my floor and couches are covered in emails. It's not like I'm signing up for everything I possibly can just to increase my collection of emails that I dream will one day be valuable. They don't get deleted because, well for no reason at all. It's just not worth thinking about. Worried about your kids not having precious correspondence to hold on to? Print it out. Worried about google having all your emails after you die? Pay a will executor to delete them for you. I just really don't understand how this is anything worth even thinking about.