As storage costs drop, storage is becoming the lowest cost in a digital repository – and the biggest risk. We examine current modelling of costs and risks in digital preservation, concentrating on the Total Cost of Risk when using digital storage systems for preserving audiovisual material. We review the vital role of storage and show how planning for long-term preservation of data should consider the risks involved in using digital storage technology. Gaps in information necessary for accurate modelling – and planning – are presented. We call for new functionality to support recovery of files with errors, to eliminate the all-or-nothing approach of current IT systems, which in turn reduces the impact of failures of digital storage technology and mitigates against loss of digital data.