I see what you mean; the iTunes music folder on the HD is quite a bit larger than what is shown in iTunes Music. Is it necessary to keep duplicates of the same albums on the HD and in the iTunes Music folder?
Is it necessary to keep duplicates of the same albums on the HD and in the iTunes Music folder?
The iTunes Music folder is on the HD.
No, you don't need to keep duplicates of anything (though you should maintain regualr backups).
When you add files to iTunes, iTunes will make a copy of the file in the iTunes Media folder (specified in iTunes prefs > Advanced). After you add to iTunes, you can delete the original.
If you move the file to the /Automatically add to iTunes/ folder inside the /iTunes media/ folder, iTune will move (not copy) the file. Then the original file is not simply taking up space.
I keep a shortcut to this folder on my desktop then move stuff here and let iTunes take care of it.