In order to be more careful, there are steps you can take to prevent being overwhelmed with podcasts and their episodes. They include:

Just because you subscribe to dozens of podcasts doesn't mean you . Sample a podcast a time or two by downloading episodes from iTunes. Is it good enough to merit a subscription? And if your listening time is limited, what other podcasts are you willing to bump to make room for this one?

If your initial evaluation of a podcast's worth or your available time proved to be off-base, launch iTunes, select the Podcasts entry, Control-click (right-click) on the unnecessary podcast, and choose Unsubscribe Podcast from the contextual menu.

Chances are that if you've accumulated more than 10 episodes of a podcasts and haven't yet listened to episodes 11, 12, and 13, you're not going to. iTunes will automatically delete old episodes for you. Just select a podcast, click the Settings button at the bottom of the iTunes screen, uncheck the Use Default Settings option in the resulting Podcast Settings window, and put the Episodes to Keep pop-up menu to good use. From this menu you can choose All Episodes, All Unplayed Episodes, Most Recent Episodes, and Last 2, 3, 4, 5, or 10 Episodes. Click OK and then click the Refresh button at the bottom of the iTunes window. All but the number of episodes you chose will be removed from that podcast's list of episodes.

You may discover that that when you hit Refresh the episode entries disappear from iTunes, the episode files aren't deleted from your Mac--they remain in the host folder you've designated for storing your iTunes files. If you want to delete them you have a couple of ways to go about it.