It doesn't matter if you are old/young, experienced/inexperienced. Performing well in your career is never a static knowledge/skills position. To continue to perform well requires continuing skills and knowledge growth, we are always beginners. The way we grow IS mostly through informal channels, whether we are 18 or 58. Perhaps the curse of knowledge is that as we grow older we only remember the formal learning of our younger years. I think that the truth is that the mass of knowledge we acquired informally doesn't sit in a memory box that's clearly labelled 'Informal Learning' so we don't actually remember acquiring most of the knowledge/skills we now have - but it did get there - somehow.