After the mattress had been used for about six months on one side and a couple of months on the other, it started to sag and was no longer comfy in the same way that foam rubber is. The most important thing is that he wrote to the manufacturer to change it under warranty, but as a consequence, during a month of disagreements, he took a video, sent different images on request, and as a result of these actions, the Askona firm refused to exchange the items, justifying this as a natural phenomenon during operation. Do not let the manufacturer's guarantee or its "quality" sway your purchasing decision.