Coding refers to the process of assigning symbols or codes to parts and materials to identify them systematically. Effective coding systems are simple, unique, compact and flexible enough to meet future needs. Coding helps organize large numbers of materials by bringing similar items together, avoiding duplicates, and making materials easy to store, identify and track. Common coding systems include numerical, alphabetical, alphanumeric and mnemonic systems which use numbers, letters or a combination to encode materials. Coding provides benefits like reduced storage sizes and easier material accounting, but risks include potential for codes to be misunderstood or forgotten.