I've noticed in the last many years that musicians aren't reading as much as they used to . When I was playing mostly horns (in the early 70s) it was much easier to learn a song with the music written out for you . Of course , then , I was doing stuff that required playing as written . But , since I've gone to bass full time , it seems to be a mostly ear thing . Now , it's nice to have a score handy for reference . But , I think you get better feel when you play by ear . It leaves you open to your own interpretations . And having a good drummer to work with makes it even better .