The biggest mistake companies make in developing a discovery process is seeking perfection. Companies strive to create the perfect policy, develop the perfect processes and purchase the perfect tool. They believe that defensibility both in court and in the eyes of regulators is achieved through saving all the right records for exactly the right time, finding all and only relevant documents and deleting older information immediately after its retention period expires.
The problem is that records retention policies and discovery processes as well as the technology tools to support them are inherently imperfect. Likewise, the interplay between the people, processes, tools and technology certainly is not perfect either. Nor does making one link in the chain of the process, such as a record retention schedule, even more "perfect" make the weaker links and the overall chain any stronger.