How do I practice deprecation strategy?

The most direct way to practice deprecation strategy is through a focused exercise: Identify one belief, process, or mental model you currently operate under that you have patched more than three times. Write down its original purpose, the patches you have applied, and the problems that persist despite those patches. Then write a single sentence: 'This schema is deprecated as of [today's date] because [reason].' You now have your first formal deprecation record.

Common pitfall: Treating deprecation as deletion. You archive the old schema with its context, rationale, and lessons learned — you do not erase it. The other failure mode is never deprecating anything, which produces an ever-growing pile of contradictory rules you half-follow and half-ignore.

This practice connects to Phase 16 (Schema Evolution) — building it as a repeatable habit compounds over time.