A couple playlists that share songs

If I make two playlists that both have the same song included, will it be copied twice onto the device?

I can’t be 100% certain (I don’t use playlists), but I believe the file will only copy once.

If the files are already on the device and you create the playlist correctly and  from the files on the device ( not on your computer), then it shouldn’t copy them again at all.