The determination of the relative value of files is important for an organization while determining a retrieval service level for its files and a corresponding file retention policy. This paper discusses via a literature review methods for developing file retention policies based on the use values of files. On basis of these results we propose an enhanced version of one of them. In a case study, we demonstrate how one can develop a customized file retention policy by testing causal relations between file parameters and the use value of files. This case shows that, contrary to suggestions of previous research, the file type has no significant relation with the value of a file and thus should be excluded from a retention policy in this case. The case study also shows a strong relation between the position of a file user and the value of this file. Furthermore, we have improved the Information Value Questionnaire (IVQ) for subjective valuation of files. However, the resulting method needs software to be efficient in its application. Therefore, we developed a prototype for the automatic execution of a file retention policy. We conclude with a discussion