I'm curious, 100 mb is not enough? If the average email is 20k that translates into 5000 emails.

If you are actually reading 5000 mails a day I'd be impressed. If the 100mb is insufficiect because you are using the service to cumulatively store important messages, I would consider that foolish to rely on a third part free service to store my important correspondence.

Even if you receive attactments regularly, you shoud transfer them to your local machine if they are important.