I think you're right. The limit has been frozen at 15GB for some time, and even if you just use gmail at some point you are going to hit that, at which point I

I think you're right. The limit has been frozen at 15GB for some time, and even if you just use gmail at some point you are going to hit that, at which point I imagine many will upgrade to avoid having to delete potentially valuable emails. I think most people now look at email as a total archive of all their communications through mail - not a 'mailbox' they prune and delete every so often.