I think that I have doubled up with my music files, When I transfer/add them to my itunes I do not delete them from the media player. I think therefore I am dulicating my music and using more space on my laptop. Should I therefore delete them from media player??
No don't delete them, you have not duplicated any of your files, media player and ipod is just looking at the same music folder, so showing the same files. they are both just music programmes that play music, they don't store your music within the programme.