I used to view pomodoro timers as good for production type work but not for creative, in the zone work. This model served me well. There have been a few surprises. I had assumed that studying was creative work and therefore would not benefit from a timer. Barbara Oakley's Coursera course "Learning how to Learn" recommends the use of a pomodoro for studying. Both the coursera course and her book "A Mind For Numbers" goes into why this is the case.