Drupal tracks revisions of content automatically, storing each saved version in the database. You can view past revisions, compare them, and revert to an earlier version if needed.
Enable revisions per content type under Structure then Content types. You can set it as the default behaviour or leave it optional for editors. Most sites enable it by default for all content types.
Revisions are essential for editorial workflows, audit trails, and undoing mistakes. They are also the foundation of Content Moderation, which uses revisions to separate draft work from published content. The Diff contrib module adds side by side comparison of revisions, which is incredibly useful for reviewing what changed between versions. For any site with multiple editors or compliance needs, revisions should be enabled everywhere. The storage overhead is minimal compared to the value they provide.