Google's John Mueller said it only makes sense to update the date on a piece of content or article when you either "write something new or significantly change something existing." He said this on Twitter and it goes along with previous advice John has given before.
John said this on Twitter:
When you write something new, or siginificantly change something existing, then change the date. Changing the date without doing anything else is just noise & useless.
— π John π (@JohnMu) February 5, 2022
John has said before that you don't need to change dates of evergreen content. But just validating the old content is still legit does not deem an updated date is required. Of course, never fake dates - that is an old trick that Google is on to.
Forum discussion at Twitter.