Records retention policies should cover any electronic records that may be located on file servers, document management systems, databases, email systems, archives, and records management systems, as well as paper copies and backup media stored at off-site facilities.
Organizations that want to retain information longer than required by law should firmly establish why such information should be kept longer. Nowadays, just having information can be a liability, so keeping sensitive information longer should be the exception rather than the norm.
At the opposite end of the records retention spectrum, many organizations now destroy records (including backup media) as soon as legally permissible in order to limit the scope (and cost) of any future discovery requests or litigation. Before implementing any such draconian retention policies that severely restrict your organization's retention periods, you should fully understand the negative implications such a policy has for your disaster recovery capabilities. Also, consult with your organization's legal counsel to ensure that you're in full compliance with all applicable laws and regulations.
Although extremely short retention policies and practices may be prudent for limiting future discovery requests or litigation, they're illegal for limiting pending discovery requests or litigation (or even records that you have a reasonable expectation may become the subject of future litigation). In such cases, don't destroy pertinent records — otherwise, you go to jail. You go directly to jail! You don't pass Go, you don't collect $200, and (oh, yeah) you don't pass the CISSP exam, either — or even remain eligible for Certified Information Systems Security Professional (CISSP) credential certification!