If musicians in an orchestra can have their music in front of them, why the hell can't folk singers. Over a number of years playing I have a quite a collection of tunes, chords and rhythms buried in my memory.
As for words I cannot even remember the name of the place I am playing in half the time,
as my eyes are getting bad it looks like i will be printing my word sheets on A3 paper.
As my style of playing is finger picking i do tend to make songs a little more complicated than the plectrum basher. So until i need braille to read the words i for one will continue
with relying on the printed word.

fisheye