Knowledge gained from personal experiences or Classroom instruction? I would say that both kind of learning are complementary. It’s always necessary to learn things by yourself, but at the same time, it is also important to learn from people who know more than you, especially from good teachers. Every time I receive formal instruction I try to make a connection between what I’ve already seen and learnt by myself and what teachers have taught me in classes. I believe none of them is sufficient by itself.