Genie, I agree, if we are talking about accompanying songs, I have probably 10,000 or more I could do straight off, by ear, no mistakes. Like every song in the charts between 1961 and 1975 for starters, plus God knows howe many traditional.

But I couldn't sing them all ( although I could make a stab at the lyrics in most cases).

Nope, if we are talking concert performance, imaginative and immaculate guitar backing, lyrics memorized perfectly, thirty songs is about the max at any given time.

Not that there is ever going to be any way to prove or disprove this ....

Murray