DVR Box Missing Scheduled Recordings And Freezing Up On Playback

Within the past few days, we’ve noticed two recurring problems with our DVR box.  First, some preset recordings are being missed and programs are not being recorded.  We get no error messages, just missed recordings.  Also, on several completed recorded programs when we play them back the recording stops after about 15 minutes and freezes up.  We cannot watch the remainder of the recorded program.  Resetting the box does not appear to fix either issue.  Is it time to exchange our DVR box for a new one?