The warranty on the new mattress and foundation you purchase is not an indicator of how long the product should be used before replacement. The warranty is there to protect the customer from product defects, not against the gradual loss of comfort and support. Moreover, different manufacturers offer different warranties, and you should check with the manufacturer of your mattress for product-specific information.

When you consider emerging technologies that continually improve mattress construction and the changing needs of your body over time, you'll understand why it's wise to compare the comfort and support of your present mattress to a new mattress at least every few years, regardless of the length of the warranty.