This obviously depends on many different factors, such as what type of ball pressurizer that you are using, playing style, brand of balls you are using, etc. However, as a comparision: without a tennis ball pressurizer, 20 % of the pressure in the balls will be gone after only about an hour of play, and then steadily decrease from there.
When using a high quality tennis ball pressurizer such as Pressurebox, with some high quality tennis balls such as Wilson or Tretorn, the playing experience is close to new balls after a few times of play, and even after 10 times of play, the hight of the bounce is usually good.
The results will not be the same for everyone, every time, and the balls will obvously look a little bit different after such a long time, the logo on the balls will no longer be visible, etc, but the playing experience will in most cases be great even after such a long time. For Padel, the playing time will be even longer, because it has even less effect on the felt of the balls.
