I would say if you are able to watch them at work , and they make it look easy and it look good to you , you may have a good Tradie , doesn't like doing things twice
Like everything else in life get the basics right ,and the flow on should be the same
When they look at the job in hand , they should know what tools/materials are needed , and if they are doing demo work,they should explain that there may be extra charges , and show why there are extra charges
When they make it look easy ,Tradie , if they struggle , might pay to let them go , I've seen some orrible work on the domestic front ,through friends of friends , and it costs four times as much to fix
Payment for materials , don't pay up front you may never see them again,pay when on site , more horror stories , then pay in full when you are happy with the finish
I always tell the client to pay me at the end when I've finished and they are happy , always been paid and recommended to others
Cheers