Sure, I've learned a lot in my first forty-odd years here on planet Earth, but in any endeavor that matters, I can still grow.
The problem is finding ways to do that.
But, the further you get, the harder it becomes. Eventually, when you're truly top-level, you have to become your own teacher, setting for yourself what the next level is and figuring out what exercises will stretch you and get you there. Our needs as learners become more and more individual and it's harder to find a "group solution" that includes you.
I'm not there yet. But I am far enough along in some endeavors, teaching and writing especially, that I'm having trouble finding things that move me forward. Where's the training for intermediates?
I went to a teaching conference recently and found that 90% of what was being offered were sessions I could have taught. Frustrating. I've found the same thing at some writing seminars and conferences.
As a teacher, I've learned to use reflective practice to help me grow. I analyze a lesson in terms of how well my students engaged and how much they retained. The next time I teach the same topic, I make adjustments accordingly, trying to figure out how to engage more people and help them retain more knowledge longer term. It's a struggle, as reflection requires time and I only have 90 minutes per workday in which I am not actively teaching. Reflection often gets shoved down the list in favor of things like providing training to others, performing secretarial tasks necessary for lessons, and keeping up with communication streams, or, you know, using the bathroom and eating lunch.
At least in writing, I set my own pace. Reflective practice is trickier. My writing is more personal than the Spanish lessons I provide. It's harder to view objectively. So, reflective practice, for me, is a matter of finding an appropriate peer group, in putting my work out there and listening to the feedback with a heart to learn. I am fortunate in my local critique group, which includes writers in a similar part of the journey as me, as well as some who are more skilled than me, and others that I can help along. I also participate in a few online critique groups and response is varied. Not everyone is there with a heart to learn.
So, I guess the key is, once again, community. A community of learners, all with a heart to learn.