- TIB – Leibniz Information Centre for Science and Technology hosts and operates a digital preservation system with three purposes: for the preservation of our own holdings, as a system which two other large German libraries – ZB MED and ZBW – use as tenants for the preservation of their holdings, and as a platform to offer preservation-as-a-service to smaller institutions. The consortial nature of the system hosted and operated by TIB is a setup which isn’t explicitly taken into consideration by documentation accompanying certification procedures so far. Neither the Data Seal of Approval nor the nestor seal foresee a tiered model, where parts of an archival system’s responsibility – e.g., the technical infrastructure – fall into the responsibility of a system other than the one who actually makes archival decisions about the content captured within. Nevertheless, TIB and ZBW separately received the Data Seal of Approval in 2015 and the nestor seal in 2017. The paper presents and critically reflects upon experiences made by TIB during the certification process. It describes the institutional resources which were required to accumulate the required documentation and how they are spread across different organizational units. The authors present incentives for formal certification and discuss if and how these incentives paid off. While combinations of organizational, technological and legal factors make for a plethora of different archives, leading to no two certification processes being the same, the outcome of this paper shall serve as guidance to those thinking about or concretely planning to undergo basic, extended or formal certification. It shall give an insight into resources required, show where potential problems may exist, but also discuss benefits of the process.