Hmmm... I'm not sure what you mean. For me it's typically the other way around: I don't know something, so I look it up. I don't have the knowledge or the skill, so I try to get it. I never find myself already having the knowledge there. I think for me there's a necessary process of 'solidifying' knowledge by applying it to a real situation, which is what happens when I really code something. I can read books about a programming language all day, I can read an API reference, but it will never sink in until I start typing.