What does it mean that beginner mind as a practice?

Approaching familiar situations as if seeing them for the first time reveals hidden details.

Example: A senior engineer inherits a codebase she built three years ago. She walks through it with a new hire, explaining each module. Halfway through, the new hire asks: 'Why does the auth service call the database twice?' She has no answer. She wrote that code. She reviewed it dozens of times. She never saw the redundant call because her expertise told her the auth module was 'done.' The new hire, unburdened by that assumption, saw what was actually there.

Try this: Choose something you interact with daily — your morning routine, a codebase you maintain, a recurring meeting. Set a timer for ten minutes and describe it in writing as if you have never encountered it before. Do not use any evaluative language (good, bad, efficient, broken). Only describe what you observe. Note at least three details you normally skip over.