Composite repairs are a crucial tool for pipeline operators to extend the remaining life of pipeline assets for over three decades. Significant amounts of testing have been completed to demonstrate the ability of a composite repair to sufficiently reinforce common and complex pipeline anomalies. However, the question remains, with composite repairs only being put in the ground for the past 30 years, how long will a composite repair be able to extend the life of a buried transmission pipeline? This paper investigates the common failure mechanisms of composite repairs, and how a prudent pipeline integrity engineer can address them through material selection, engineering design, full-scale testing, and proper installation. Long-term strength and cyclic fatigue analysis both must be accounted for in a composite repair design and test, as well as applicability to the anomaly in need of repair. Once the tenants of proper repair guidance are reviewed on a theoretical and full-scale test basis, a case study is shared on a 25-year old composite repair. The testing that was completed to demonstrate the long-term effectiveness of this repair is reviewed to determine remaining life of the composite repair for this anomaly. As a result, operators will have a framework to be able to evaluate composite repairs and make an informed integrity decision on their propriety for remediating the pipeline integrity threats found on their assets.