Accelerated aging is a form of product testing in which a product is subjected to stress which is meant to mimic the aging process. While it is possible to evaluate products as they age naturally, accelerated aging allows people to determine roughly how long the product will survive in the real world without having to wait for the product to break down naturally. This allows companies to test new products before they are released without having to wait for weeks, months, or years while they monitor natural aging to determine what the shelf life of the product might be.
For some types of products, accelerated aging tests are required, for the purpose of generating expiration dates. In these cases, the test results may need to be submitted to regulatory agencies so that they can be verified. In other instances, accelerated aging is used to identify issues which should be addressed before a product is released. For example, if the packaging breaks down very quickly during accelerated aging tests, a company might opt to change packaging to avoid this problem.
In these tests, products are subjected to very intense stress far beyond that which they would encounter in the real world. This can include mechanical stress, as with equipment which is run hard to see when it starts to break down, along with temperature extremes, humidity changes, physical trauma, and so forth. The idea is to simulate the process of aging within a very short period of time; which the product might not be as abused in the real world as it is during accelerated aging, the cumulative stress endured by the product over a normal lifetime can be equivalent to that simulated in accelerated aging.
As the accelerated aging progresses, data about how the product holds up is logged. This is then used to extrapolate a potential shelf life. Some issues people think about when performing such tests include: how exposure to UV light might affect the product, exposure to corrosive materials, physical trauma during shipping, and radical temperature changes, among many other things. If possible, these conditions are simulated to see what happens to the product.
Some companies perform their own in house accelerated aging testing, using equipment they have in their lab. Others may send products out for such testing to third party laboratories which can conduct the testing. This may be done for increased reliability, or because a company lacks facilities to do the testing.