The environmental impact of clothing could be reduced by extending garment lifetimes, and many clothing retailers are now exploring design for longevity as a sustainable approach. In order for products to meet durable design standards consistently, global supply chain processes must be managed and controlled to avoid quality problems and early product failure. This paper uses a single case study to explore the challenges of meeting specified durable product standards in production by tracing and observing the identification and resolution of a quality issue affecting the durability of luxury knitwear. The research demonstrates that new tests and processes could enable durable products to be produced more consistently, but also identifies the obstacles and limitations to implementing these enhanced procedures. The paper proposes that effective production management of durable clothing may be more difficult within global supply chains where differences in business culture, operational practice and knowledge exist between companies. Supply chain models that emphasise shared values, knowledge and information exchange, trust and collaboration are considered as the most effective in delivering sustainable products. It concludes by identifying a range of conflicting priorities between commercial and sustainable practice that must be addressed to achieve consistency in durable clothing production, and makes recommendations for industry and future research.