As in my hard drive. I'm not very diligent about it. I have a nice little USB 2.0 bus-powered 80 GB external hard drive to which I back up my iMac. And I'm doing that this am. I'm at 2 and a half hours and it's not done with files yet. That seems too, too long. I really should get a massive firewire drive to do regular back-ups but I don't like monopolizing another great hunk of desktop real estate and I also like the convenience of a bus-powered drive. Even if it is slower.
My hard rive could actually not back to the drive if I didn't have a script to exclude iTunes and iTunes files. I've got just short of 20 GB in iTunes as it stands and I really don't think it's necessary to back them to the spare drive. I have all those files on my main iPod anyway.
And the final note. How do you know when you did your last back-up? I slap a date label on my drive so I know. My last back up was in February. That's not nearly often enough. How do you back up?
UPDATE: Done and done in 2 hours 47 minutes and change. Not too bad really.