Hi aron82e,
While warranty exclusions and even warranty length can give some indication of the confidence a manufacturer has in their mattresses … warranties themselves don’t cover the loss of comfort and support which is the biggest reason people need to replace a mattress. A warranty is not generally an accurate indication of how long a mattress will last any particular person. Knowing the materials in your mattress is generally a much better way to predict the durability of a mattress and how long it may last you than a mattress warranty. There is more about warranties in the first part of post #174 here.
Phoenix