With the rapid technological changes, digital preservation, i.e. the endeavor to provide long-term access to digital objects, is turning into one of the most pressing challenges to ensure the survival of our digital artefacts. A set of strategies has been proposed, with a range of tools supporting parts of digital preservation actions. Yet, with requirements on which strategy to follow and which tools to employ being different for each setting, depending e.g. on object characteristics or institutional requirements, deciding which solution to implement has turned into a crucial decision. This paper presents the DELOS Digital Preservation Testbed. It provides an approach to make informed and accountable decisions on which solution to implement in order to preserve digital objects for a given purpose. It is based on Utility Analysis to evaluate the performance of various solutions against well-defined objectives, and facilitates repeatable experiments in a standardized laboratory setting.