I'm not sure how they manage it. Perhaps they do program it to refresh itself. At least they're smart enough to automate the process, if that's the case. I know the HDD stops spinning when the unit is "off", unlike the HRs that I had. Of course, that means that when you do power on there is no buffer. What I do know is that I used to have to manually reboot my D* receiver at least once a week, usually more. I have had to shut my Hopper off and unplug it once since I got it in early April. That was about a month ago, after a firmware update. No problems since then.