Set a "lifecycle date" for an article
When creating an article, you can set a "lifecycle time" that would determine how long the data within the article is valid. When the time limit approaches, the author (or you can designate a group) is notified that an article is about to reach the end of it's lifecycle. The author (or group) can then review the article to see if it is still accurate, update as necessary, and then restart the new cycle.
This would work much differently than assigning an expiration date from an article as assigning an expiration date would remove the article and that's not what is wanted.