Time Machine can only back up one source for whatever weird reason. Like most people, I have multiple external hard drives and I can't back all of those up to one single location because drives of that size simply don't exist. Basically I just want backup software that is incremental and is simple and cheap, and can execute multiple backup tasks. I don't need anything else. I've looked at the usual apps but many of these seem strangely outdated (such as Mac Backup Guru). I've searched on the App Store but when I type in Backup, I get a bunch of apps that don't seem to be for backup. When I type in "incremental backup", I only get ONE result, Backup Buddy, which I currently use but I'm not happy with it (when the backup disk fills up with old backups, you have no other choice but to format it and start over from scratch, and it doesn't tell you how long the backup is going to take or anything useful for that matter, really). It also tells me that my 3TB drive won't fit on an identical blank 3TB drive, and then goes ahead and does the backup anyway. Thanks!