Tools used by me that most would assume would be my basic hand tools, refrigerant guages and multi meter. These are the basic tools I would say that would get my job finished. Everybody associates a technician to have a tool bag with these items or at least which items they have heard of. The unknown could be the specialty tools I have that not only point me to the direction of the problem but to tell you how in depth we need to be to fix the root  not just the symptom. I like many in my trade have swapped to a more digital form of diagnosis.  Old car mechanics say I cant work on new cars because its just a computer, well todays HVAC is the same. I can do more with a computer today than I can with a simple nut driver. What is the point to have access to technology if you dont use it.