I had a small group of engineers, and our job was to diagnose problems in nuclear plants. We definitely had to be in the plant for testing, and due to the complexity of the data analysis, back in our lab for analysis. However, writing test reports and a some of the other work could be done anywhere. We always had a huge amount of overtime because of the nature of the job, so we'd still have had a lot of time in a plant or in the office. I'm not sure about teleconferences because you really do have to get out the crayons for some of the people who think they need in on what you found. Overall though working from home makes a lot of sense - I absolutely hated the commute - more than even trying to deal with some of the people whose job it seems was nothing more than making your job harder.