The National Library of Technology (NTK) has operated its institutional repository for publications and other outputs for over ten years on the open-source platform Invenio 1. With a lack of technical staff over the years, the maintenance of the repository was getting more and more complicated. By 2022, the situation was no longer sustainable, and we had to face difficult choices. To ensure the repository's sustainability, it was necessary to change the software and process the data migration. We chose DSpace 7 as it meets our requirements well. Nevertheless, there are only a few implementations of DSpace 7 so far, none of them in the Czech Republic (only version 6). In all circumstances, it meant many challenges and mistakes during the DSpace 7 implementation. Our experience with the sustainability of a repository on a short budget is very fresh. We want to share it with the community, so our mistakes don’t have to be repeated. The contribution briefly describes the NTK repository context and shares the challenges and mistakes we made while implementing the chosen solution.