Three Years.
It's been three years since Sherlock Holmes died. Three years since John came home and saw the envelope on the mantelpiece, his name written in Sherlock's handwriting. He hasn't been able to bring himself to open it, hasn't even lifted it from its spot in three years. Just seeing that handwriting wrenches his heart, makes tears well in his eyes, bringing back memories of a life he used to live.
He'd quit his job at the clinic a month after Sherlock's death, he couldn't handle being around people. Everything had seemed to remind him of his late best friend, someone wearing a long coat, an overly arrogant child, a man with curly hair. Sarah had tried to convince him to stay but he knew she understood. Instead he took cases, from anyone that would give him one. It was the only time he ever saw Sherlock, when he was trying to solve a mystery. It was because of this that he tried to never be without a case that way Sherlock was with him all the time. It wasn't the same as when he had been alive, but it was better than nothing. John didn't think he could have survived without Sherlock there.
He'd stopped seeing Sherlock about a year ago. He'd been out on a case, Sherlock by his side, helping him through the process as he always did. Sherlock smiled at him as he solved yet another one and said, "You don't need me anymore John," before he slowly faded away. John had given a sad smile, he hadn't protested, knowing that after two years it was time for him to move on.
About a month after Sherlock left he dropped the cases and got a job in the ER. It wasn't a glamorous job but he helped people and it made him feel good about himself. People still reminded him of Sherlock, if he heard a deep voice he would have to turn around, just to be sure. It still hurt just as bad as it had before, still brought tears to his eyes, still made him feel sick to his stomach. Nothing had changed, except now he could deal with it. Now was the time, he would finally open the letter.