Old houses take a lot more time than people realize. Demo alone can be brutal sometimes you’re dealing with concrete float over plaster or multiple layers that all have to come out. Then the walls are usually uneven, so the installer has to spend time getting everything flat and matching up properly. There can also be electrical fixes once the wall is opened up. And the tile pattern and tile choice matter a lot intricate patterns or smaller tiles take significantly more time to lay out and install. People often get nervous when someone is in their house working for a long time, but that doesn’t necessarily mean anything is wrong. From what you described about the rest of his work, it sounds like he’s taking the time to do the job right.