The disk drive is very easy to replace on the Roamio models. The hardest part is opening the unit itself. Once you have it open you just take out the old drive, put in the new drive, close it up and turn it on. The Roamio automatically downloads the latest software and will download your One Passes from tivo.com. The only hassle is that the recordings that were on the old drive are lost unless you copied them to a computer before removing the drive.
This easy upgrade works if the drive hasn't failed, too. If you buy a model with a 500GB drive you can replace it with up to a 3GB drive to have more space for recordings without paying a premium for a more expensive model.
