In the grand scheme of document retention, one component is your law firms’ storage of your legal files. Federal laws may set some minimum periods of retention as might state laws, but otherwise it behooves a law department to set its own expectations. I noticed that one law firm, in its engagement letter (See my post of Nov. 5, 2006 for related citations.), states that “Generally, at the conclusion of each matter, we will retain your legal files for a period of five years after we close the files.”
It could be that the requirements (or advantages) for a law firm to retain client files differ from the requirements (or advantages) to do so by the law department. A law department in that situation might include in its guidelines for outside counsel the precaution to check with the department before the firm destroys any files.