When you learn something you can't unlearn it. >>"then unfortunately is replaced by other things" I don't think that is how it works! To answer your question

When you learn something you can't unlearn it. >>"then unfortunately is replaced by other things" I don't think that is how it works! To answer your question: The best way to use what you have learned is to share it or to connect it to something your are interested in. I highly doubt high-school Physics would inspire one to become an astronaut, but it some how helps to see the things in a better way. Always share what you learn and keep learning. At some point your subconscious works things out for you.