The box spring is an integral part of any mattress set. Some box springs are more rigid and serve primarily as a foundation or riser, while other box springs feature torsion modules, or even springs, that shock absorb and help extend mattress life. It is often found that the real cause of an uncomfortable mattress is a defective or sagging box spring. If your mattress and box spring are both over 10 years old, you should strongly consider replacing both pieces when buying a new sleep set. Newer mattresses, especially today's one-sided products, are designed to work specifically with their corresponding box spring. Realize that with some exceptions, mattress manufacturers do not offer a warranty when purchasing a mattress without a box spring. Our comfort consultants will be happy to help you determine if you need to replace your entire sleep set, or just your mattress.