They really last a long time
I was given a box of these balls by a pro who was encouraging good environmental practices (hooray!). I then bought a case of them online because I liked them so much. They are more expensive, but really do last at least twice as long as pressurized balls. If you have the need to play only once with a can of balls, these might not be cost effective for you (though the lack of plastic packaging is still good for the environment), but if you hit with balls longer than that, these are great. They retain their bounce a very long time. The pros at several parks where I live all use them now for lessons and liveball.