Carol Ann Tomlinson says:

Excellent teachers never fall prey to the belief that they are good enough. The best teachers I have known are humbled by how much more they need to learn. They don't add to the chorus of voices chiming, "I already do that."
High-quality educators are determined and often voracious learners. They seek daily to understand their content more fully, to probe the mystery of the young lives before them more deeply, and to extend their pedagogical reach beyond yesterday's boundaries. They know that the parameters of their own lives are extended every time they extend possibilities in students' lives.
These teachers seek out the best professional development opportunities. They read about education. When a district or school fails to support their learning meaningfully, they become their own professional developers.
This is what excites me about leading staff development and interacting with teachers across the district.  When a recent snow day forced our upcoming all-district staff development day to be replaced by a student day, one teacher approached me to voice her frustration.  She was looking forward to our staff development agenda.  This teacher knows she has more to learn.

A few months ago, I suggested that educators, like students do not always know/realize what is in their best immediate interests and I still believe this to be true.  The best teachers know they don't know.  They look for opportunities to learn more about what they don't know.

I'm not 100% sure what this looks like in practice, but one thing we are trying to do in my district is use feedback loops to plan future staff development.  By asking teachers to answer a short digital survey after a staff development day or afternoon, our district leadership team can examine the responses and look for themes that arise during our planning.  Results are shared with the entire staff and these themes are articulated at the next in-service to make connections between learning experiences.  It's a work in progress, but we believe it is creating a more focused staff development environment where fewer people are asking "why" and more educators, like the one mentioned earlier, are instead chomping at the bit to learn more.

What are other buildings/districts doing to systematically make staff development viewed as a continuous process rather than an isolated event?