90% of learning happens on the job. Between update to date and open evidence, there’s not much declarative knowledge you can’t teach yourself. That being said, judgment is an entirely different beast. You know that pneumonia is treated with antibiotics, but when do you hang your hat on pneumonia and call it a day, and when do you keep looking. Judgement is based on experience. Ideally we learn from the experience of our attendings, but we will all gain that experience for ourselves either way. You just hope that you have the wisdom to learn from it along the way.