Both of these match my experience. When I was living off the wages of a young intern, I was working or learning almost every waking hour, and sleeping on a sheet on the floor because I didn't own furniture. But, whenever he group would go out to lunch, I'd go, for the socialization -- it was very consciously the only thing other than rent&utilities that I spent money on. (Fortunately, we had some amazing strip mall restaurants nearby that weren't too expensive.) When the group didn't go to lunch, I'd usually get by with whatever food I could scavenge, because I was so busy, and felt like I had to always be in the office. I hadn't yet even tried to figure out how to make and bring a lunch.