As other materials, polymer parts and goods have a limited lifetime. As we can see on the following figure 'Durability-Diagram', durability depends on the one hand on formulation including, apart the polymer, reinforcements, protective agents, plasticizers and numerous more specific additives. On the other hand, the complete part history, notably the processing parameters such as temperature, shear, residence time, and the storage conditions can alter the part properties...
If the mechanical degradations are well known (impact, abrasion, tenacity...), electrical characteristics can also decrease and, in the end, all the properties including sensorial ones, for example, colour, gloss, touch, odour... can be sufficiently affected to discard the parts and goods.
Durability is important from all the points of view: technical, economic, marketing, and ecological. In reality, doubling the lifetime halves raw material and energy consumptions, processing pollutant emissions, down times etc.