Valentin showed up 15 minutes ahead of the promised time. We made a quick review of the problems and he concluded that the 5 problems I showed him were only 2 clogged showers.
He explained the solution to 2 of the problems that I could remediate myself easily, which I did. He explained the problem another plumber had left, so I know how to claim a repair for the poorly done job.
While he worked, he explained what he was doing, and left everything impeccable.
His manner is very professional, respectful and cheerful. He will be coming back to more repairs at my place.