When you go out to buy a new mattress you should do so with as much information as possible and with your eyes wide open. Have you ever looked inside a spring mattress? In order to do so, you would have to rip off the cover. Most people would not do that. What are they hiding? They are hiding light-weight foam and fibre that softens and sags prematurely. Unfortunately, this is not covered by warranty. They call that normal wear.