How to Write a Song

I throw away quite a bit but not that much because usually from the moment I come up with an idea I kind of get a sense of if it's a keeper or not. Will you keep those bits and pieces around maybe use them in another song some other time? Sometimes yeah there has been cases where I have blended two ideas together and it's worked so I think my last album North Hope and Misery the chorus was from a completely different idea I had. Would you re-write a song if someone told you it wasn't cutting the mustard? I'd never re- write a song I'd always write something new.