After watching a number of older clips of top players, such as Gonzales, Laver, Rosewall, Newcombe, Conners, and Ashe, I have noticed something interesting, and wonder if anyone else has the same impression. Obviously today's players can hit the ball harder than those past champions listed above. The hardest shots from a Federer, or Del Potro, or Nadal, or pretty much anyone you care to name, using today's equipment, are more powerful than the hardest shots from, say, Laver in his prime, using a wood raquet. I don't think anyone would seriously question that fact. What I noticed watching the old clips, however, is how often those older players did NOT hit their hardest possible shot. My impression is that they typically hit groundstrokes at perhaps 75-80% of their maximum power (the maximum power they could generate with the equipment of the time), waiting for a chance to attack and THEN hit the full-power shot (or simply attack the net for a volley). In other words they seem to be "saving" their best stuff for the right opportunity. By contrast, today's players mostly (mostly, I say, I know their are exceptions) seem to hit all out, all the time, putting maximum effort into nearly every shot. Not only can they hit harder than the players of the past, but they spend more time using maximum power. I'm not saying here that either way is "better" than the other, or "the right way to play", or anything like that. Both styles simply reflect the practices and strategies of the respective eras. I'm just wondering if anyone else finds this to be true.