See this is the thing , I think the two main things that define define a good hair transplant . That is graft survival and donor quality . extractions are fundamental and require good manual dexterity which trained Doctors tend to have over techs . The extraction process and the way they are handled is the main factor in them surviving . Look at bisanga, albeit I think kostis helps him now but he a doctor too who does all the extractions , never see one poor yield from him. Freitas who uses techs. I’ve seen poor yield on some Patients on the Spanish forum . Pinto, villa and Ferreira all do extractions and always produce high yield