I just ran into this again.
The legendary cellist Pablo Casals was asked why he continued to practice at age 90. He replied “Because I think I am making progress.”
In this time of applications and competitions and auditions, it seems good to remember that, at least ideally, music is a long term endeavor!
Sorry for typo in title!
Just used this quote in another thread, so thought I should come over here to say I loved it. Totally the right mindset for a musician at any level.
And for the rest of us too, whatever our interests and pursuits 
My S and I were talking about Pablo Casals and this quote not too long ago. Casals revolutionized how the cello is played. He didn’t learn to play that way though so it embodied his whole mind set about playing that he was constantly learning and inventing new ways to play and practice. Definitely a good mindset for any musician to have!