On the radio in the UK today Country Joe MacDonald was explaining about that distinctive 60s sound that he and his band developed. And he put it down to having a crap Farfisa organ and no tuning aids!

I do like to have a tuner for my stringed instruments as when I tune them I'm sure that they're in concert pitch. I can't complain that people aren't in tune with my squeezebox and harmonicas (which I can't tune) if I'm not prepared to be 'in concert'. Playing with others is great fun, and quite instructive, but it rather depends on everyone being in tune with each other. Tuners really help here, as everyone can tune independently and get to the same place.