How do I avoid duplicates when adding MP3 folders

Question

I have a folder filled with MP3 songs that I have added to iTunes via the "File > Add Folder to Library" function.
I frequently buy and add additional MP3 songs to that folder (My Music/MP3) and then re-add that folder to iTunes so it adds the additional songs to my library.
Usually, iTunes recognizes that I already have most of those songs and just imports the new ones.  However, if a song that has already been imported before is changed in iTunes (say, for example, you change the artist name from "The Beatles" to "Beatles", then the next time I re-add that same folder to pick up the new songs it also thinks the songs I changed in iTunes are different, new songs and I get a duplicate.
Is there a better way of doing this that results in no duplicates?  I suppose I could keep creating and adding new folders every time I add new songs, but that would get messy fast.
Thoughts?

Answer 1

The default path for the iTunes library folder is C:\Users\<User>\Music\iTunes.
The default path for the media folder is C:\Users\<User>\Music\iTunes\iTunes Media.
Both can be edited; the media folder via Edit > Preferences > Advanced, and the main library path by holding down shift as you start iTunes and using the choose or create library option.
Ideally you want the iTunes Media folder inside the iTunes folder as this puts the library in the portable shape that is easy to move between drives, migrate between computers, and backup.
You can use Edit > Preferences > Advanced > Reset to reset the media folder to the default path inside the library folder, or click the change button if required.
When you change the media folder iTunes should offer to consolidate the library. This makes iTunes make a new copy of any track currently located outside of the media folder inside the media folder and connects the database to that new copy. Once complete it is up to the user to do the house keeping of cleaning up the originals. Alternatively I have another script called ConsolidateByMoving whose purpose should be obvious.
There is another option that controls the internal structure of the library. With new libraries it should be set correctly, but a library that has been migrated from iTunes 8 or earlier might still be in the old shape. If you go to File > Library > Organize Library and find the "Rearrange files..." option is not greyed out then you should tick this and click OK.
See also Grouping tracks into albums.
tt2