Get a load of this old post where the guy was worked on (by James) for, like, the whole day:
Just based on what I’ve read here, thermolysis seems to be the most common in North America, supposedly more in the eastern half. It seems like most Europeans and Australians who post here are getting blend or galvanic.
The largest area covered in one sitting could be as large as you want. There are only limits for small areas. Places like upper lip, eyebrows, etc, can’t be worked on for more than 20 or 30 minutes in one sitting.