Right! UPS! I have one between mine and the wall too, so I can even keep recording during a power outage! (This is a lot less true now that I have a pre-amp hooked up)
For the drive replacement, I wouldn't necessarily replace on a schedule. You'll notice the drives are on the way out when the unit freezes up doing deletes, or artifacts show up in recordings on channels you know should have none. Once this starts to happens, boot into Kickstart-54 mode and run a drive check. The tests take a LONG time, but you'll know whether you need to replace or not for sure.
Do you run a pre-amp in your setup? I've heard of people having issues with the Premiere and pre-amps (ie. inserting a pre-amp causes the Premiere's tuner issues)
I'd love to upgrade to a Premiere for the improved UI and streaming speed. The Tivo HD streaming is horribly slow.
Chimney mounted CM4228 UHF Antenna with CM7778 preamp - Sony KDL-46XBR4/Hauppage HVR-1600/Tivo HD