Hi paddyb,
This is a fairly “standard” reply that really doesn’t mean much because they are talking more about “comfort” than about durability and these are two completely separate issues because you can’t “feel” the quality or durability of a material. While 100 days would certainly be enough to decide whether a mattress was “comfortable” and was a good match for you in terms of PPP … it’s not nearly long enough to be able to assess the durability of a mattress.
When you mention this to most companies they will usually tell you that the warranty will “protect” you but mattress warranties only cover manufacturing defects and they don’t cover the gradual (or more rapid in the case of lower quality comfort layers) loss of comfort and support that comes from foam softening that is the main reason that most people will need to replace their mattress. In other words warranties have little to nothing to do with the durability or useful life of a mattress or how long it will be until you need to buy a new mattress. If there is an actual defect in the materials it will usually show up early in the life of the mattress (usually in the first year or two) but knowing the quality and durability of the materials in your mattress is always a much more reliable way to assess the relative durability and useful life of a mattress than the length of a warranty. There is more about mattress warranties in post #174 here.
The “somewhat good” news is that the 3 lb memory foam layer is only 1.57" thick so it’s not as risky as having a 3 lb density memory foam layer that was thicker.
Phoenix