Retirement might prove an obstacle to this quest. I think Federer this past year has been really driven to prove himself one last time (despite what he says). Now that he won #17 and beat the weeks at #1 record, if he also manages to win gold at the Olympics I could see his motivation start to wane by the end of this season. I hope I'm wrong and that he continues to play forever, though.
This is fairly insightful. Sufficient motivation in terms of goals is a key in continuing to play and improve. Federer already had more records than anyone. Still he kept playing and looking for new goals. I think there are more keys. One other is the love and passion in playing the game. These, Mr. Federer seems to have in abundance. As long as he remains relatively healthy, I think he'll go on playing till he stops enjoying tennis as much relative to other things in his life. He'll make new goals, 100 or 110 titles is one, 8 Wimbledon titles would be another. I think he'll stop when tennis becomes too great a hindrance to his family life or for health reasons.
I know this is a thread about Federer, but I'll contrast this to another great player, Mr. Nadal. He's been quoted before saying he's lost his passion at times. He often distracts himself by doing other things. Now Rafa has achieved his biggest goal - 7 Roland Garros titles
, and passed the great Bjorn Borg. He's won the Olympics, he's won Davis Cup. He's done everything on clay that there is to do and has won majors on the other surfaces. There is one other great goal that he has wanted - the Masters Cup - but it may be that he feels that it is out of his reach due to it being on indoor hard court.
I wonder how much longer Rafa will drive himself to play single's tennis. I may be wrong, but I don't think he loves the game in itself with the passion of Federer, and there is nothing wrong with that. His physical health - knees - are probably a limiting factor as well. I think it is healthy to want to move on and do other things and he is obviously has the resources to do that. The next few months should tell us the story with Nadal. I think Nadal could play for the next 4 or 5 years without issues if he focused on clay. The question would be, for what reason? Was Wimbledon 2012 following Roland Garros #7 Nadal's Waterloo, or will Nadal bounce back and set more goals - Vilas sits on top with 45 Career Clay titles - why not Rafa for 50 (see my thread)?