Obligatory warning: This script has been designated as an obsoleted "Retro Script". There is no guarantee that it will function as described with modern versions of iTunes and/or macOS. If used in its current form it may not work at all without modification and, at worst, it may corrupt or destroy data.
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.
downloaded 8m 20s ago
Export album artwork as folder.jpg to Album folder
downloaded 15m 46s ago
Move selected playlists to a new or existing folder
downloaded 32m 28s ago
Search allmusic.com website (AMG) with data from selected or playing track
downloaded 33m 53s ago
Add or subtract a user-entered number from each selected track's Plays
downloaded 43m 24s ago
Set choice of various number tags of selected tracks incrementally
downloaded 47m 21s ago
Batch set new Last Played/Last Skipped of selected tracks