@administrator
Glad to reply with my experiences.
My range topped out at High C (above the staff) since I entered college in 1967. I would work at it over the next twenty years but without instruction.
My first real lesson (age 40+) was with a symphony chair who immediately started me on long tones and Earl Irons. Ten or fifteen years later i joined a community band. My C was pretty advanced compared to the other players, but it was not strong all the time. Then I played more often and started practicing more. Was accepted to the Jazz band sub group and started being more challenged. I participated in the Mendez Institute (DU) and took a lesson from Al Hood (DU). Then a lesson from Marcel Marchetti (USAF Falconaires) - then changed my practice routine and started keeping notes. Then the Jazz band leader became Tom Fowler from Wichita State Jazz program. Charts became professional level and the lead part required Ds and Es and an occasion F or G (above the staff). Started a daily routine three ring binder with with bits from Adam, Fink, Schlossberg, et al. Use it every day. Integrated with this was more play time (I retired) so I am playing 4+ - 2 hour rehearsals a week. Then I added Hickman's Beyond the C.
That is what I have been doing now for about five years. My workable range now includes an E above the staff and I am working on the F.
Take Aways:
Important factors for Range Development are:
Professional Instruction
Multiple methods and sources
Motivation
Time
Practice
Patience
If I had all of the above when I was 18, I may have developed a reliable above the staff range perhaps to the coveted DHC.
However, although I enjoy listening to Maynard, I really don't care for the current lead music that depends on the extreme register. The repertoire that I want to play does not include DHC. So if I can play the E and perhaps the F, on a regular basis, (and musically), I will be happy and satisfied. Of course, achieving that goal and then maintaining it, at age 70, will require constant practice.