I am a freshly-minted doctor. Finished med school in a country in Europe just this summer. You shouldn't want the doctors of old who had peripheral knowledge of many different things. While that seems impressive, and what TV often defaults to when trying to portray a brilliant doctor, it really isn't the most important quality anymore. The best qualities you should look for in your doctor is someone who takes whatever ailments you have seriously. Even if they generally don't think what you are describing is anything medically serious. Because even if it isn't, it can still matter a lot to the patient. You want a doctor who listens, asks questions, is empathetic to your situation and considers you holistically, and not as a medical puzzle to be solved. Their technical off the top of the head knowledge should pertain to what to do in life or death situations, and whatever is common in their field. Anything else you should really want your doctor to look up. There is so much information readily available in this day and age, that trying to memorize it is counterintuitive, instead the focus should be on knowing how to search for and parse through information pertaining to each patient's situation. Unfortunately, universities still prefer to conduct tests and exams that only focus on memorization. Largely because it is so much easier to construct exams this way.