First off MTTF and similar metrics are used for situations with a constant failure rate. failure rate information and provide estimates suitable for each time frame. In my non scientific mind constantly updated electronics such as cell phones .new model after new
model follow new model have a mean time for failure I honestly believe from my personal past experience that one model will last until the next model comes out and then it will begin to fail consequently that is why my poor little galaxy s5 suddenly began to court failure as the Galaxy x.6 was released.
Samsung I see how this works.