University College Dublin became the first library in the Republic of Ireland to trial patron-driven acquisition (PDA) as a collection development tool in 2013. A total of 42% of UCD Library's book budget was allocated to the project, which included both electronic and print books. This article describes the twelve month project from the tender stage, through evaluation and selection of supplier, to the final money being spent. We analyze which disciplines spent the most money, and how usage of PDA titles compared to non-PDA orders placed in the same time period. Finally, we assess the impact of PDA on the library's workflow.