A field with few recent values may still feed an old report, integration, routing rule, permission check, or quarterly workflow. Deleting it too quickly can create a silent failure; keeping every field forever makes the schema harder to understand and maintain. What evidence do you require before retiring one? A workable process seems to need an owner, usage checks across automations and exports, a deprecation period, a replacement mapping when definitions changed, and a recoverable archive of old values. How do you handle fields that are technically populated but no longer trusted?