This post is meant to stir some discussion on how you manage your photo archives. I use Apple Aperture but the same discipline could easily apply to Adobe Lightroom or any other Digital Asset Management (DAM) system.
My management system is a little different. Like others I import new projects into standalone libraries. There I make all image selections, apply all adjustments, apply all metadata and ratings, etc. When I'm done with this I merge the project library into my master library. The machine on which this initial edit takes place has Time Machine so incremental backups happen every hour at worst. I can always tell Time Machine to make a backup right now so that I don't have to wait for the next hourly backup to roll around.
My master library is a managed library and is stored on an external 1TB USB-powered My Passport from Western Digital. I have three more of these exact same disks. I use rsync from a Terminal window to update these three copies from the master. The master and one copy are with me everywhere I go. The other two copies are kept at home. I keep a copy in addition to the master with me at all times in case the master fails while on the road. Because I keep my master as a managed library, I can lose the master drive and simply start using one of the copies as the new master until I purchase a replacement or have Western Digital replace it if it us under warranty. I don't have to worry about reconnecting images to a library.
I love these My Passport drives. They are commodity drives @ $90 each, and I can get them pretty much anywhere. I also like that they are USB powered so no extra power cords to drag around. They are also USB 3 so they are super fast on the MacBook Pro. Syncing them is fast and easy which encourages me to do it often so that I know I'm covered.
How do you manage your archives? Do you have a DAM?