When producing large systems, it is important that the requirement decomposition process is performed correctly, with requirement traceability maintained. This paper explores this area, using examples from industry to illustrate the problems which can be encountered if traceability/decomposition is not performed correctly. It is hoped that this paper will assist the reader in generating a more precise definition of some general system engineering concerns such as when decomposition needs to be performed, with the requirements hierarchy extended. For the problems covered, this paper also suggests methods by which they can be alleviated or recognised once they have occurred. This additional information is primarily aimed at people who are using tools to manage their requirements, as there may be mechanisms to automate these methods. This paper presents the personal view of the author, based on his many years of experience in this area.