You can change the interval that Mail.app waits before it refreshes RSS Feeds. In order to do this, open up a Finder window and go to /Applications » Mail. Control-click on Mail and pick Show Package Contents from the pop-up menu, then navigate into Content » Resources » English.lproj. Make a backup copy of the RSSPreferences.nib file you see there -- if something goes wrong, you'll want to have that copy to get things back to normal. Double-click on the RSSPreferences.nib file (you'll need to have the Developer Tools installed); this will open the file in Interface Builder. Double-click on the Check for Updates item, and select one of the drop-down menu items. Make a duplicate of this menu item from the Edit menu, then click on one of the duplicates. Go to the top and hit Tools and make sure the Item Attributes window is in your workspace. When the duplicat...

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