In my industry and experience, our ES's are referenced on the drawings as applicable to the product. The ES is an integral part of the product development process and are reviewed or developed when the products are being developed, or possibly later in the product life if there are failures. Reviewing for review sake is not efficient in my opinion. If a product is developed with a specific ES and is in the market for several years with no issues what is the value in reviewing the ES?? I an updated model of the product is developed, you would review the ES to ensure it is applicable and appropriate and move on with changes or not...System approach.