Little Hurdles: Mac : Outlook 2011 : Archiving Emails to save space on Exchange Server

I use Outlook 2011 for Mac as my primary Email client backed by Microsoft Exchange server. We have limited storage space on Exchange Server, to a limit that every two months, I get email message that my storage is almost full. As I mentioned, nothing unusual, everyone faces this problem.

Here are the list of problems, I wanted to solve. I wish, I had unlimited Exchange storage so that these problem would not exist in first place.

Automatically move my emails to a backup folder or drive.
I should be able to retrieve my old emails pretty easily

Here are the list of Solutions

Manually backing up emails into backup data file, 'On My Computer'

Export the selected messages to 'On My Computer' folder of the Outlook 2011

Moving emails to gmail A/C

Create a gmail A/C and move all the old email there. This solution might not work for everyone because of corporate security requirement.

Please see the URL below in Reference section. Those article provide a great deal of details around concept with which we are dealing with here.