The process of making music was "easier" in the past Paul has told BBC Click's Spencer Kelly.
Big Beatles' hits like Michelle and Yesterday could be recorded, mixed, taped and done in one day, he said. But new ways of working meant that a song no longer needed to be written before a musician went into a recording studio to put a track together.
Paul said he advised young musicians to write their songs first: "It sounds obvious but people don't do that so much these days." More at BBC.com/Click and @BBCClick
