Let us explain:
How durable the product is declared from manufacturer's advertisement, how long of the service life, it is not a loose talk. It is achieved through rational design, proven by proper and adequate verification testing.
The above service life test is usually carried out before the product development, these samples will not be into the market, they are also engineering test samples.
Some of responsible companies will be regularly and randomly sampling to test during mass production to see if they meet the certification criteria. Of course, in order to ensure the consistency of product quality, every part of the product will go through a recognized process, and there will be raw material inspection to ensure that the specifications and standards are consistent so as to ensure that the finished product meets the quality requirements.
Under normal circumstances, the finished products must be scrapped after all the above service life test, not allowed it to put on the market, consumers can use it in rest assured.