The improvement of the life time of materials is both an economic and environmental issue. The stress and level of exposure of the materials are very different depending on the application: thermal resistance for high temperature operating materials, mechanical stress for dynamic uses, electrical stress for electrical devices… Furthermore, in practice materials can be exposed to several types of stresses at the same time or successively during their life. The level of protection of polymers must be adapted and improved in order to include all the types of stresses and thus enhanced the durability of the materials. This also means a better understanding of the degradation mechanisms according to the different stresses experienced by the material. It is also important to develop prediction and simulation tools, based on experimental works and mathematical models, which will allow us to determine the long-term ageing of polymers and the evolution of their properties. A better understanding of the mechanisms of ageing of polymers will enable to better control, predict and enhance the durability of the materials we use every day.”