I have 3 external drives. 1 - 1TB and 2 500GB. One is used for photo backup, one is used as a complete computer backup, one is a time machine (Mac) backup. I do a full computer backup at least once every 2 weeks. I back up all my memory cards after shooting with both RAW and JPEG files. I load JPEG files into Aperture for PP (combo of Aperture and Photoshop PP done) and then posting on Nikonites Project 365. I also use DropBox for backup of work related files.