Brain Attic

Lets start with a quote from a great man, sir Sherlock Holmes.

A man should keep his little brain attic stocked with all the furniture that he is likely to use, and the rest he can put away in the lumber-room of his library, where he can get it if he wants it.

Taken from The Five Orange Pips, page 225.

Sounds great, but how in the world we implement such a thing? How we divide information bits by bits and separate them to be useful or less useful? But then again, useful or less useful in the term of what? job? personality? one human being in a community? lots of question here.