One of the hardest questions to answer is: how long does it take to write a song?

If you’ve been watching the New York Times’ splendid series, Diary of A Song, you might notice some songs come in a flash, like Ed Sheeran’s Shape of You -  cracked in a 3 person collaboration within 15 minutes - while others are a never-ending mission, like Bon Iver’s iMi which took 5 years, 28 people and a piece of cardboard! 

If there is huge variance in the time it takes to write songs between fantastically successful…