John Mueller from Google mentioned on Google that relabeling the old contents as new without any major changes leads to a bad SEO strategy. It is disrespectful to the users when they figure it out and it does not give users the honor that they deserve to get.
John mentioned that SEO hacks can never make a site seem great. Your content must give users the respect that they deserve to have. From a user’s point of view, when he realizes that old content is being repackaged as new, it destroys any potential that the user through the site can have.
He further emphasized that it does refer to the fact that you stop maintaining the old contents. Keeping old content is fine but relabeling it without any actual change proves to be a disservice on the part of the site. Maintenance, deleting, and upgrading content to ensure that it does no go out of date is a good method. It is not a guarantee of a high rank but not maintaining it feels even worse for the user’s side.
See the forum discussion at Twitter.