The final step in any product development cycle is validation of the product design and manufacturing process. The ability to meet a life target is normally one of the most important attributes. This data can also be used to estimate warranty costs and repair or replacement revenue.
The challenge is how does one test a product that is used continously for a number of years? No one wants to test a 10 year expected life by testing samples for 10 years.
It is universally accepted that under certain circumstances accelerated life testing will reliability predict product performance. MDDI had a great article explaining use of the Arrhenius reaction rate function to perform accelerated shelf life testing at elevated temperatures allowing months of shelf life to be simulated in hours. Likewise MIL-STD-202G, Method 10 describes methods for testing PCBs via thermal shocks to simulated years of use in hours.
Accelerated life testing is critical to quickly finding persistent failure modes and estimating product life before warranty returns and customer complaints start pouring in.