Hi Jimhjr3,
I’m not eml of course and hopefully they will see your post and reply but they returned their mattress under a warranty replacement which means that their mattress would have had visible impressions that were measured as 1.5" or deeper.
This is fairly common for major brand mattresses because of the lower quality/density foams they usually use in their comfort layers. Lower quality/density materials will soften and break down more quickly than the higher quality/density materials that are used by many other manufacturers although in many cases the the visible impressions aren’t deep enough to qualify for a warranty exchange even though foam softening (virtual impressions) can result in the loss or comfort and support and the need to replace the mattress. In these cases (which are very common) there would be no warranty coverage even though the mattress may need to be replaced. eml was fortunate that the impressions in their mattress were deep enough to quality for a warranty exchange. Mattress warranties only cover defects not the loss of comfort and support that comes from foam softening so they have very little to do with the durability and useful life of a mattress. There is more about mattress warranties in post #174 here.
Phoenix