Dealing With Redundant, Out-Of-Date and Trivial (#ROT) Content
▻http://www.smashingmagazine.com/2015/06/11/dealing-with-redundant-out-of-date-trivial-rot-content
The best approach is to establish a policy to enforce content review. This will make sure content producers check their content to ensure it is not out of date. For example, this might need people to log in to the content management system once every six months to check their content.