How to backup all your incoming and outgoing mails?

It's so simple I'm wondering why I haven't thought of it before. GMail. Set up a new account, like yournamebackup@gmail.com. Add it to the automatic bcc: setting of your favourite email client(s). Set up an autoforward (keep mails on server) on your email host. (I go for the least work, so I just made a .forward file like this in my home directory:

myusername
mynamebackup@gmail.com

- so just a copy of my mails are forwarded to gmail.)

Voilá, you have 2 GBytes (and growing) backup of all your incoming and outgoing emails. Neat.