Founded in 1996, the Archaeology Data Service (ADS) is a discipline-specific digital archive. After twenty years, the organisation curates over 320,000 digital objects comprising over 2 million files and amounting to 10Tb of data. As the amount of data held continues to increase, so do the challenges of ensuring preservation, management and access. The paper presents practical case-studies from the ADS, focussing on our procedures for ensuring data integrity, and the result of a recent migration of vector images. The paper also examines accessibility and re-use, as well as the practical challenges of presenting large datasets.