Hi darkarchon,
[quote]Do you think the T&N Ten will sink more over time compared to the T&N Five? Or should it provide more support over time?
I am just wondering if the foam thickness (ten inches vs five inches) makes any difference in the durability of the mattress. Or is it simply thicker to handle perceptions that good mattresses are thicker. [/quote]
The most important factor in the durability of a polyfoam mattress is the quality/density of the polyfoam (in this case about 1.8 - 2 lb polyfoam) and both the 5" and the 10" use the same quality polyfoam. A thicker mattress may be a little more durable however because there is more foam to spread out and absorb the compression forces when you sleep on it so the percentage of compression in the foam would be a little less which can reduce the wear and tear on the mattress.
There are several benefits to a thicker mattress though. One is that thicker mattresses are less likely to bottom out under more concentrated weight or heavier body types.
You could use them on a slatted foundation rather than a solid surface like a floor or a solid surface foundation because you would be less likely to feel the slats under the mattress (particularly with heavier weights).
It would also raise the height of the sleeping surface which would be easier to get in and out of bed for some people.
A thicker mattress also has a wider range of compression from soft to firm which would make it more adaptable for higher weights (and it would probably feel a little softer as well) although lighter weights may not notice any difference in “feel” between them. There is more about the effects of thickness in post #14 here.
Of course the tradeoff for greater thickness is that it’s heavier, a little more costly, and a little more difficult to move, transport, or store.
Phoenix