This is a subject that has always haunted me. I have played for the best part of 40+ years, I play classical guitar. I alway have about 8 songs that I play. The 8 songs change, I bring in other songs to the mix, but push about the same number to the side. When I talk with another classical guitar player, I always ask should I be memorizing songs. For the most part they always answer the same way: don't worry about it, have 6 or 7 that you can play and then use sheet music. That's what I do.
Then I get thinking, I've played for 40 years, if I memorized one song a year, I'd have quite the repertoire.
Tom