Back pain and poor sleep quality are often blamed on the mattress feel — soft or firm — when thickness plays just as big a role. A mattress that is too thin can bottom out under your hips and shoulders, while one that is unnecessarily thick may feel unstable or trap heat.
As a general rule, side sleepers and heavier body types benefit from a thicker mattress (25cm or more) that gives the support layers room to cushion pressure points. Lighter sleepers and those who prefer a firmer, close-to-the-ground feel often do well with a slightly thinner profile.
The construction underneath the surface matters more than the number on the spec sheet. A well-zoned pocket spring core with a modest comfort layer on top can outperform a thick but poorly layered mattress, so always check what is actually inside before choosing based on thickness alone.
If you are between two options, our Compare Collections table breaks down the exact construction of every Diamond Mattress model side by side, so you can match the build to how you actually sleep.
