Don is quite right about the preparation care and preservation of the voice. I have no problem with anything that he has said because I certainly want to be singing when I get to be an old lady. I do make sure that my vocal apparatus is warmed up as best it can be ( singing in the car on the way, joining in choruses prior to the set, avoiding smoky atmospheres ) for the very reasons that he has stated.
But I take issue with those who think that using PA may be indicative of poor vocal technique. Given the poor acoustic ambience at many folk clubs, PA can make it possible to sing a quiet highly ornamented lyrical piece without worrying about whether those people on the back row can hear every note and syllable above the police sirens, aircraft and general city traffic noise.