GUGUSOFT  No, you don't need multiple scripts. You can use one script for all your apps you want to quit.

For example:

tell application "iTunes" to quit

tell application "Mail" to quit

and so on …  
(Version 4.8)

GUGUSOFT  With iTunesShut 4.8 you can use your own AppleScripts. That means, that you can use a simple line of AppleScript code to quit any application you wish.

Open AppleScript Editor and type for example: tell application "VLC" to quit

Then in iTunesShut choose "AppleScript" from the pop-up button and then choose your script.

That's all!  
(Version 4.8)

GUGUSOFT  Duro, you are welcome! I am glad to hear, that you find iTunesShut useful. For questions or more comments email at gugulino1@mac.com.  
(Version 4.2)