One hander
Rookie
NCAA has a great rule that I think should be implemented amongst the pros ASAP. If you leave the court or call a trainer, it costs you one point when you come back. This is such a great idea. I am not a fan of Zverev but completely agree with him that the only reason players do this is not to treat injury or deal with some issue they are having, but rather to throw off an opponent who is playing well. Djokovic has now made this standard practice whenever he goes down 2 sets or feels like the momentum is turning against him. Even Nadal did it to Federer at Wimbledon semi-final after losing first set, Federer was so annoyed and put off, he easily lost the second. Now, even Alcaraz is doing it. You should not be able to do it to throw off an opponent who is playing well. In fact, I think it should be two points and your opponent gets to choose if he gets those two points in either the very next or following game (your serve or his). Only exception I would make is if both players mutually agree beforehand on very hot day that they would both take a break after first or second set to freshen up.