Now that it's being mentioned, the sleep timer seems to work sporadically for me. Some times, it would cut off at 30 minutes just fine. Some times, and I can't pin it down, it doesn't seem to work. I have noticed this with Audible books, since I don't have many MP3 files that long. Of course, it's been hard to pin down as well, because I fell asleep and can't remember if I slept long enough <grin>. Testing the sleep timer can be disorienting sometimes.