Keep learning!

Let me advise you to pursue the same course through life, recollecting that, even as practitioners, you must still be students. Knowledge is endless, and the most experienced person will find that he has still much to learn.

Sir Benjamin Collins Brodie, speech to students at St. George's Hospital, London, in 1850, quoted in Bill Hayes, The Anatomist: A True Story of Gray's Anatomy (New York: Ballantine Books, 2008), ch. 5 (citing The Works of Sir Benjamin Collins Brodie, vol. 1 (London: Longman et al., 1865)).