The law of accumulation is different to that of growth and refinement.
One can accumulate all sorts of things. Just go into peoples attics, basements or garages! You will see much that has accumulated over the years. Much of those items have a history with them that might have significance in one's past. But accumulation of experiences do not equal growth unless there is thought and direction that can sort out what needs to be dropped off and what needs to continue and what needs to go through a refinement process and journey. This is governed by the motivating force of one's musical or life goals at any given time throughout a person's life.
So, there is a natural discarding or letting go that takes place on the journey-quest isn't there?
Like, maybe we don't have to write the slide positions over all the notes anymore.
Maybe we don't have to take a certain breath in a piece we've been working on anymore because our breathing has changed and we have more embouchure efficiency. But, maybe we still find mouthpiece playing useful so we continue it and find more effective methods in it's practice and further applications.
Think of the things we will always need as brass players.
-Air (lungs and diaphragm, etc.)
-Embouchure (teeth, lips, facial muscles etc.)
Those aspects will certainly change throughout our playing career so don't be alarmed when they do! Good MAINTENANCE PRACTICE will keep you in touch with your needs.
Change can really alarm people when it seems to threaten their playing for example. Maybe we are not supposed to play the same our whole lives. Maybe our view of what is good playing needs to find a new outlet and viewpoint so we can continue to the next levels. Maybe those levels are UNKNOWN and they are not based on the criteria of what we thought good playing was or is.
Think on this: Our bodies do not maintain a youthful form forever. (I know that!) Either do our sounds, ranges and technical facilities stay youthful forever. Can we find the expression through what we can do at any given level? This is really a contemplation for players who are feeling the effects of 'age'. You do not need to be 65 to feel this change. It can happen at anytime. This is the value of 'playing' with the territory and being in touch with our physical, emotional and mental selves, (a three overlay system) so we can move with the changes and make course directions, pit stops and tune-ups along the way. It is vital to EMBRACE these changes and not AVOID them.