As long as it takes me to find someone who knows how to do it and promise him Dove bars if he'll change my strings for me. Theoretically I know how, but in practice, I still haven't mastered that part of my guitar education. (But then, I'm still learning how to use a pick, so it's not as if i"ve been at this forever ... )
But this is why it's nice to be able to carry a tune without accompaniment, yes? Or to have a close, personal singer who can.