My DVR is constantly stating it is near or at full capacity. Unplugging the DVR to force a reset helps, but it doesn't last more than a few days. I know when it's getting to be a problem when I press the record button while watching TV and it comes up with a message for "create a manual recording" only with the other options grayed out. I have replaced the DVR once, but it hasn't helped. I could try replacing again.
Also, not sure if this is related, but sometimes I can't search for upcoming shows by title. It can't find anything.