A Thousand Years
It hadn't taken long for Sherlock to realize as a child how much it unnerved the adults, the others. He would try to hid himself away, make himself as unnoticeable as conceivable. They didn't appreciate his genius, and to this he was privy in acute ways. But he knew. He knew that he would always have his intellect, his own self to save him from the world. He receded further into himself, which only proved to the detriment of others: for he grew exponentially when most people reached their zenith for a fraction of second, then proceeded to decay in the dank corners of a world they only to care to light marginally.
It was dark out there. But he found solace within the faces of those who he inspired envy, loathing, disgust. Rendering those beneath him dumbfounded.
In any matter, he quickly learned that his observations must also be obtained quickly. It didn't help to add the sting of the stare to the sting of idiocy, and often, his subject matter became unnerved anyway. Inaccurate readings make for dragged-out cases. It became so...boring.
John, though...John he lingered on. And it didn't escape his notice.