The Sleep Council recommends replacing your mattress every 7 years to maintain an optimal sleep environment. But ultimately the only way to determine the lifespan of your individual memory foam mattress is by considering the quality of the foam and how you take care of your mattress. We’ve included some info about those points below too. We would expect an average memory foam mattress to support and comfort you for 10 to 15 years. More expensive, higher density memory foam mattresses can last even longer – and cheaper items will likely wear out faster.