Keywords: re-use re-using GTIN barcode allocating
GS1 has issued a Decision Support Tool to help you decide if a new GTIN is required.
Broadly the principles are that the brand owner is responsible for allocating GTINs and each variant of a product must be identified with its own unique GTIN.
The complete Rules may be found at http://www.gs1.org/1/gtinrules/
GTINs that have been allocated and used once may never be re-used. Re-use was permitted except on medical and pharmaceutical products until November 2018 subject to various conditions but it is now forbidden.
The Bar coding basic user guide V3 discusses re-using item numbers. Note that the information it contains is now INCORRECT. An amended version is pending.
Version 2 issued 6 November 2018