Hi zebo42,
Most good retailers will facilitate and act as the intermediary with warranty claims so that their customers don’t need to deal directly with the manufacturer and this would be part of the service they provide.
I would also take any warranties longer than 10 years or so with a grain of salt because longer warranties are more about marketing than they are about the durability or useful life of a mattress or when you will need to buy a new mattress. There is more about mattress warranties in post #174 here. It’s also true that many smaller manufacturers would be much more likely to replace a mattress that is in the grey areas of their warranty coverage because they are more focused on building and maintaining their word of mouth reputation for quality and durability and the ones that make higher quality mattresses will also tend to have less warranty claims.
While there is no way to quantify how long any mattress will last for any particular person … if a mattress is well inside the comfort/support range that is suitable for someone and isn’t close to the edge of the range that is too soft for them when it is new and meets the minimum quality specs that are suggested in the guidelines here then it would be reasonable to expect a useful lifetime in the range of 7 - 10 years and with higher quality and more durable materials like latex or higher density memory foam or polyfoam (in the comfort layers especially) it would likely be in the higher end of the range or even longer.
It’s always more realistic to think of about 10 years as a maximum reasonable expectation for any mattress no matter what the quality or durability of the materials and then treat any additional time after that as “bonus time” because after about 10 years the limiting factor in the useful life of a mattress will often be the changing needs and preferences of the person sleeping on the mattress and even if a mattress is still in good condition after a decade … a mattress that was suitable for someone 10 years earlier may not be the best “match” any longer.
Having said that … with higher quality materials throughout a mattress and/or for people whose needs and preferences or physical condition or body type hasn’t changed much over 10 years then “bonus time” or even “extended bonus time” with higher quality/density and more durable materials like latex or higher density memory foam or polyfoam or natural fibers is much more likely than with less durable materials.
Phoenix