I purchased this mattress over 3 years ago, off the showroom floor with no warranty. The first 2 years were great but as time went on the canoes started forming on our kingsized bed. We even turned the entire bed 90 degrees to try and wear it down. Long story short there's a small mountain in the middle of the bed (well it feels like it!). I haven't measured the canoe depths but they are probably around 1-2 inches on each side where we sleep - I could not roll to the middle of the bed if I wanted to. As a stomach sleeper this depth simply does not work for me.