iTunes will stop updating a podcast if you have not listened to at least one of its episodes in five days. This script will batch-update every podcast subscription so you don't have to manually update each one individually.
I have posted instructions on how to create a launchd agent to run this script automatically and invisibly in the background to ensure that your Podcasts are always updated.
Possible iTunes bug (July 17, 2014): Looks like the iTunes AppleScript command updatePodcast command is broken as of iTunes 11.
OBLIGATORY WARNING! Because this script has been designated as a "Retro Script" there is no guarantee that it will function as described and may even corrupt or destroy data.
Perform search-and-replace on text in your choice of tags
Enter text for the selected tracks' Description tag
Continuously update your desktop picture to current track's artwork
Convert or import tracks with any encoder on the fly
Rename selected tracks' Song Names with their filenames (minus extension)
Edit a selection of iTunes tracks' tags in single window