I would never try to talk any one out of buying another guitar { I own 4 myself } but when I saw David Wilcox this year he did it all with only one. And he retunes usually after 1 or 2 songs. Granted - when people were shouting out requests he was letting them know that he was planning to do those songs later in the set when he got around to those tunings. But that's the advantage to being a solo act.