I've got a 50D and a 7D, and regularly shoot 500-1000 frames over the course of a weekend of cycling events. I've been told that, after I'm done loading all the images onto my computer, doing whatever editing needs doing, and organizing my images on the computer, I should clear my DCIM folder on the CF card rather than formatting the card.
If I've got another file on the card (maybe an enhancement file like Magic Lantern), it makes sense to avoid purging the entire card. I've not tried this approach, and don't even know where to find the folders on the card.
The manual didn't seem to have any info regarding this, and googling didn't produce much, so.......
Can y'all enlighten me a bit?