Twenty years ago format obsolescence was seen as the greatest long-term threat to digital information. Arguably, experience to date has shown that funding and organisational challenges are perhaps more significant threats. I hope this presentation helps those grappling with these challenges and shows some key advances in how to use knowledge of costs, benefits and value to support long-term sustainability of digital data and services. These are the slides from my keynote presentation to the Digital Preservation Coalition and Jisc joint workshop on Digital Assets and Digital Liabilities - the Value of Data held in Glasgow in February 2018. The slides summarise work over the last decade in the key areas of exploring costs, benefits and value for data. The slides posted here have additional slide notes and references to new publications since the workshop and some modifications such as removal of animations. One day I hope to have time to synthesis this presentation in an accessible way as an article but hope this slide deck is a useful interim resource.