If you want to create a playlist that contains a particular artist or genre for example, then you can define rules to keep these custom playlists up-to-date.
Smart playlists are ideal too if you regularly sync your i Pod, i Phone, or i Pad, and want to keep the songs on them up-to-date.
Simply add *'s to your search with or without other keywords. This makes it possible to find songs by the Beatles with three stars without having to resort to a Smart Playlist. To get the most out of smart playlists, you really need to have complete tag information.
Some of my favorite third-party tools are: i Eat Brainz - This free program examines songs in your library and then creates an auditory fingerprint of the sound of each song to match it with the correct information maintained in the Music Brainz Database.
As of i Tunes 8, this no longer updates the playlist.
I think the Podcast rule is a bug and for all I know it's fixed now.
I just avoid it and use *Genre contains/does not contain Podcast and that seems to work just fine for me in most cases. If the only way it knows to change out a song is when one of the intermediaries does so, and that intermediary playlist isn't on the ipod, then it will not change your ipod's smart playlist 'till itunes boots up again.
Is there a complete (or mostly complete) list of what conditions do this?
From what I've experienced, these break live updating on i Pod smart playlists: *Podcast is stars My speculation is that the Playlist and Album Rating rules break live updating because the i Pod doesn't do the complex calculations that those require.
It does not have a rank yet, but my other one doesn't either, and they told me it was fixed in 10.2 Beta.