Again, the answer to this question will depend on the model you buy. Some coccyx cushions are stronger and more long-lasting than others. The best coccyx cushions can last for five years or more without losing their shape or firmness too much. Poorer quality coccyx cushions generally tend to have much shorter lifespans, so if you want to get the best bang for your buck, it makes sense to invest in a top quality model with a long lifespan and a lot of durability.