Or maybe she has a learning technique which allows her to do all the things together, including the fun side. What works for one person might not work for the other. Some people prepare one exam for months, some for a few weeks. Some stay in their rooms for days and nights, others can easily go out almost every night. Who knows maybe she has a really good memory so she doesn't need to much time to rememer. I think it's great if you can allow yourself to relax even when you prepare for an important exam. Pushing your brain overtime can do a lot of harm. That being said, I almost destroyed myself 2 years ago with my exams and I wouldn't wish that for anyone!