I like how you have the .bkf files set to 5 GB, but you may want to have them set to 4 GB. By doing this you can copy the files off onto standard DVDs, allowing you to have a point-of-time archive. This is something i do for my company, but not on a daily or monthly base.
This may not be the best way, but i go back and review the time stamp on the .bkf files. When not needed i simply delete the file, then delete the items in the media set.
Hope that helps.