Econ, I was a math instructor at the college level and it was not unusual for me to put in 60 hours a week especially when I was teaching unfamiliar classes. You are correct that not everyone puts in that kind of time but many in the teaching profession do especially the ones that are innovative and get the best teacher ratings. Who knows how good this lady was or how many hours she put in but apparently she felt underpaid and I am sure that she considered the benefit of getting summers off in her decision to go into a different field.