Sofa cushions tend to ware out and soften. The foam rubber inside sofa cushions is one of the most expensive parts in a couch and will need replacing from time to time. When replacing sofa cushions use a quality foam rubber that is more expensive if you don't want them to fail. Cheap foam rubber will feel great in your sofa cushions for a short period of time before failing. We follow a rule when recommending foam rubber for sofa cushions.