Connors could play and win into his late 30s because the game was less explosive, physical and dare I say professional then. Federer is doing a great job to be in the top group at 31 but by 33 I would think he'll drop off the pace. It's just too physically demanding now. By the way look at the old footage of Laver waddling around with a decent pot belly at the end of his career and still knocking off big wins. Just would not happen now.
“There is no best. There is just the discussion of who is best. Federer, he will always be in the first part of such a discussion.” Rino Tommasi