I realize that there is nothing absolute you can say about practicing, but a few generalizations, I think, can be made. For years I practiced one to one and half hours as day and the progress was truly glacial. When I retired last year, I started practicing two hours a day just about every day. The progress after one year of this is quite noticeable. The upper register is more solid and sounds better. I tended in the past to play things down low if possible, but now when I play something like Beseme Mucho (B minor on alto), it is quite effective in the 2nd octave. I also invented a system of improvisation based on the 17th century Partimenti (Naples School),and this,combined with more practice, has upped my game in the solo area. Still, two hours a day does not a great sax player make. I think to get to the limit of your ability, you need to do many years of five and six hour practice days. It takes, I believe, an extreme amount of practice to re-wire your brain to function at a very high level. Starting young, of course, is also almost necessary. The upshot is that I will never be a particularly great player due to starting very, very late (age 60), and only practicing two hours a day. But I will continue to get better perhaps into my 80s.