EDIT: I have always kept one backup of my photography files on an external hard drive. Now that I am moving to Lightroom from Capture One I am finding there are many more things that need to be backed up. Right now, I have my system set up like this: 500GB boot drive backed up by 500GB external firewire drive. 1TB "photography drive" backed up by matching 1TB drive in an external eSATA enclosure. I am using Time Machine for that. I guess the question now would be is it worth the extra cost of a third back up (2 hard drives in my case)? If so, I could use the third drive as a second back up but what would be best: 1. 2 working drives in raid 1 with 3rd drive as time machine backup 2. 1 working drive with 2 time machine backup drives in raid 1 3. 1 working drive with 2 separate time machine backup drives I should mention that I will go through at least 1TB of storage per year. I am using Seagate Barracuda 7200.11 1TB Hard Drives that cost $320 each. I will replace my photography hard drive and backups of the photography hard drive each year but my boot drive and boot drive backups will not be replaced. I don't have the luxury of investing in expensive hardware raid set ups as I do want to keep as much money in my pocket as possible. I'm pretty meticulous and haven't lost anything to speak of in over 5 years of digital photography so I want to be safe but don't want to break the bank doing it.