For search snippets, when is “updated” more useful than “published”?

Discusses whether snippets should expose update dates for volatile information.

For concept pages, the publish date can be enough. For prices, limits, deadlines, rules, and version-specific docs, I want the review or update date visible before I click. The problem is that generic update dates can mean a typo fix, not a real review. When should a search snippet show “updated” instead of “published”?