Originally Posted by THUNDERVOLLEY
Sampras felt he had given his all to his career, and wanted to leave on top--winning a major. It be pointless to continue in major after major, revealing to all the worlds that many have your number and your "prime" is just a distant memory of the past. Think of Federer: he barely won another major after two year bust, and then USO '12, AO '13arrived and passed, with Federer's skills dulled in both. then, there was the Olympics, where he was soundly defeated. He is at the exact point of Sampras--more or less--and needs to consider his legacy.
Hiis legacy means continuing to get to the semi-finals on a regular basis.
It's another record that you will never see the likes or Rafa achieve as his body breaks down, and it remains to be seen if Djokovic can pull off anything remotely similar.
I'd say as long as he can stay in the top 5, what reason is there for Fed to stop unless he just gets tired of the grind? Since he still has just as much if not more hope of knocking off the other top 3 in comparison to the rest of the field, he can help to preserve his own legacy.