Seriously there’s some point behind which it would get pointless to keep playing. He should play as long as he has a shot at an ATP title, finds pleasure in playing and doesn’t risk his health too much.
The only people I really appreciate being born are my family and people I admire....
Federer is neither.
And Federer should retire because he's stealing the spotlight too much from the younger generation.
Whereas I don't say Rafa is stealing the spotlight from the younger generation, because Rafa is winning slams and therefore deserves the spotlight.