Here is the mechanical story. After years of nightly load, the foams inside every mattress collapse, and collapsed foam never springs back. Once that happens the mattress stops spreading your weight, so your shoulder and hip spend all night carrying pressure on two small points, which is why they complain first thing. The worn springs underneath are all connected, so every movement rings through the whole bed. Nothing about that is age. It is component fatigue, and you would condemn any other piece of equipment that far gone.
You have been trained by mattress retailers to wait for the half price sale, and fair enough too, because the sale never really ends. The trick is that the price gets marked up so it can be marked down, and the "was" price is doing the selling. We do it differently. Our prices are set from what the mattress costs to build plus a fair margin, every day of the year, which is why a queen that would carry a $1,299 tag under a showroom's cost structure is $599 here today, tomorrow and at Christmas. There is no better price coming. This is the better price.