Create, document, use, and revise work products as necessary to ensure they remain useful.
The phrase “establish and maintain” plays a special role in communicating a deeper principle in CMMI: work products that have a central or key role in work group, project, and organizational performance should be given attention to ensure they are used and useful in that role.
This phrase has particular significance in CMMI because it often appears in goal and practice statements (though in the former as "established and maintained") and should be taken as shorthand for applying the principle to whatever work product is the object of the phrase.