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What firmness you need
Firmness is the hardest thing to buy remotely and the most common reason a mattress disappoints. Part of that is because the scale everyone quotes is not a standard.
The scale is not a measurement
There is no agreed test behind a firmness number. One maker's medium is another's medium firm, the same mattress feels different to two people of different weights, and the figure quoted is usually a judgement rather than a reading. Two beds both described as seven out of ten can feel a long way apart.
So the number is a starting point for conversation, not a specification you can order against.
Firmness and support are different things
Support is whether your spine stays in the line it holds when you are standing. Firmness is how the surface feels in the first few centimetres. A mattress can be soft on top and fully supportive underneath, and it can be hard as a board and support you badly.
This is the distinction that causes most of the trouble. People with back pain are often told to buy something firm, buy something very hard, and wake up worse, because a rigid surface holds the hips up and leaves a gap under the lumbar curve. The support they needed was underneath. What they changed was the surface.
What actually decides the right feel for you
| If you | The surface needs to | Which usually means |
|---|---|---|
| Sleep on your side | Let the shoulder and hip in while holding the waist | Softer at the surface |
| Sleep on your back | Fill the lumbar curve without lifting the hips | Middle of the range |
| Sleep on your front | Stop the hips dropping below the ribs | Firmer at the surface |
| Are heavier | Resist bottoming out through the comfort layer | Firmer, or a denser layer |
| Are lighter | Allow enough give to contour at all | Softer, or a thinner layer |
Couples are the genuine difficulty. Two people of different weights and different sleeping positions do not have one right answer, and the compromise usually suits neither.
Why you cannot decide this in a showroom
Ten minutes lying on a bed with your shoes off tells you what a mattress feels like when you are awake and self conscious. It tells you almost nothing about what it does across seven hours of sleep, through the phases where you lie still for long stretches, or on the fourth night when your body has stopped noticing the newness.
Firmness preference also moves. It shifts with weight, with age, with injury, and with the season. Whatever you choose today is a choice made for the person you are today.
How to work it out properly
Sleep on it. Not for a night, which tells you only that it is unfamiliar, but for several weeks, which is long enough for your body to stop reacting to the change and start telling you the truth.
How the Perennial handles it
Two feels arrive in the bed. Four more exist. You sleep on it, and if it is not right the comfort layer changes for one that is, in your own home, with the mattress staying where it is. That is Adjust to Desire.
The first change is complimentary in the first year. You do not choose the feel at the point of sale. You discover it, and then we make it that way.