Well, in my view it is solely down to whether self-employed or not. If the former we provide refreshments only. Otherwise a tip of about 15%.

Piano tuners in this country do not make big bucks. But if they are very good yes then tip, if not good and that means average to poor then no tip.

My comment to Bob above is that you were obviously rather hurt by this man's response. From what he said I would take that to mean " wasn't needed" as a neutral adjective! I would still believe in your original thought, as being correct so don't worry yourself.