Tennis Sport

How much of a wear and tear sport is tennis?
Can the pros keep playing forever or is there an age that they should retire?
Wear and tear in tennis can come in various things. Tennis elbow, rotator cup, golfers elbow, knees, feet, hands, back, and mind. Yes some players get mental burn out. I suffered from tennis and golfers elbow from hitting my backhands and serves too flat with a stiff racquet that I had strung too tight for too long. Shoulder (rotator cup) from hitting serves to flat and hard with the stiff high tension racquet, foot blisters from too much time on court, hand blisters, lower back and after 6 hours a day 5 days a week with 5 tournaments in my last 7 weeks before quiting, maybe a little mental burn out. But if a player can rest, recuperate, get massages, physio, and other treatments he or she can last to play into their 40′s without taking a break like Andre Agassi. Not at his level perhaps but still competitive enough to still enjoy it. Or for the ladies, Martina Navratilova.
