Yeah I feel you on that, the fieldwork stage of the job can get tiring really fast, especially with the more routine stuff like asbestos and LNAPL spills. Vapor intrusion work is less of a bear, we're doing a lot of that lately and it's nice because it's indoors in the winter. I work in a larger company with a variety of projects so I'm not always doing the same thing and that definitely helps. In my current company people do tend to graduate out of the field positions fairly quickly (like 5 years) and move on to a desk job or at least a partial desk job but those first few years when you're in the field a lot can be hard and maybe impossible if you have any dependents that keep you from traveling.