If you are like me, you like to have all the information you can, available 24/7 at your fingertips. That includes e-mail. I never delete anything from my Trash. That way, two years from now, I can go back to an e-mail thread I had with a colleague today.

Most people aren't like me, and don't need to keep everything. However, it's probably a good idea to keep at least some history. That way, if you need to look up an e-mail address from 6 months ago, it's there.

So what's the easiest way to purge your old e-mail? Using Smart Mailboxes, of course! Here's how it works:

First, you need to create a new smart mailbox. To do this, Control-Click (or right-click) in the left-hand pane in Mail, and choose "New Smart Mailbox...". Enter an appropriate name, and make the necessary changes to retrieve all mail older than one year (as I have done in my example below):

In case you can't read it, the criteria is:

Date Received is not in the last 1 years

You will also want to check the boxes below to include messages from Trash and Sent. When you are done, hit "OK".

Now, you have a new Smart Mailbox located in the left-hand pane in Mail containing all mail older than one year (see sample below).

To purge (or permanently remove) these old e-mails, simply delete them! To make it easy on you in the future, leave this Smart Mailbox in tact, and then check it periodically for new entries (those older than one year). When they crop up, delete them. It's as simple as that!