It is necessary to determine the purpose of digitization and the intended use of the digital items (i.e. safeguard access through digital management, preserve the original materials through access of digital copies, improve usability of material through digital manipulation, etc.).
Unless the material at hand is unique and/or a master copy is required (i.e. hand written margin notes in the book or manuscript that are of value, etc.), the material may not need digitization if an acceptable digital copy can be found elsewhere.