On my previous iPods and iPhone, I've always used live updating smart playlists to keep my music fresh. By adding the simple rule to not include anything played in the last "x" number of days, any song played would disappear from the playlist. In other words, once you play it, it no longer fits the requirement for the playlist, so it drops off, creating a continuously updating, self-contained playlist. I just noticed that my iPhone 4 no longer does this. The playlists do not update until they are synced in iTunes. Does anyone know a trick to fix this?