How long does a mattress last
Seven to eight years is the usual answer. The useful answer depends on what is inside it and who has been sleeping on it.
The short answer
Lay a straight edge across the mattress and measure the gap at its deepest point. More than about 25 millimetres and it is finished, whatever its age.
That measurement beats any rule of thumb, because two mattresses of the same age under different people on different bases are not in the same condition.
Lifespan by construction
| Construction | Expect | How it fails |
|---|---|---|
| Cheap foam, no published density | 3 to 5 years | Compression set. Loses height invisibly. |
| Dense foam, 48 to 72 kg/m³ | 7 to 10 years | Same, considerably slower |
| Open coil | 7 to 10 years | Springs lose tension as a unit |
| Pocket sprung | 8 to 12 years | Comfort layers go before the springs do |
| Latex | 10 to 15 years | Resists compression set far longer |
| Hand-built natural fillings | 12 to 15 years | Settles, and can be re-tufted |
Foam fails without looking any different
This is why people sleep badly for years without suspecting the mattress.
Polyurethane foam is a cellular plastic, and repeated compression gradually collapses the cell walls. That is compression set, and the mattress loses height and support while looking identical. There is no visible sag, no lump, nothing to point at.
Density is what predicts how long it takes, measured in kilograms per cubic metre, with decent comfort layers between 48 and 72. Almost nobody publishes it, and at the cheap end that silence is informative rather than neutral.
Steel does not age this way. A pocket spring unit that is not abused holds its geometry for a decade and more, which is why spring-supported mattresses generally outlast foam-supported ones at the same price.
What shortens it
Slat gaps over about 7.5 centimetres. The mattress sags into the gaps, and this is both the commonest cause of premature failure and an exclusion in almost every guarantee.
Never rotating it. Head to foot every two to three months spreads wear.
Body weight. Heavier sleepers reach further into a mattress, so foam-supported constructions soften fastest under load.
A solid platform base with no ventilation, where moisture collects underneath.
Sitting on the same edge daily, because edge support is where mattresses fail first and is rarely specified below about 400 pounds.
The signs, in order of reliability
A dip over 25 millimetres. Measured, not judged by eye.
You wake with pain that eases within half an hour of getting up. That pattern is mechanical and points at the bed.
You sleep better away from home. Hotels, spare rooms, holidays.
You can feel the springs, or hear them.
It has visible mould. That is the end of it: mould cannot reliably be removed from within fillings.
What is not a reliable sign: age alone. A well-made sprung mattress on a good base at ten years can be sounder than cheap foam at four.
What a guarantee actually covers
Mattress guarantees typically cover body impressions beyond a stated depth, commonly 25 to 30 millimetres measured with the bedding off. They typically exclude normal softening, stains of any kind, and damage from an unsuitable base.
Two of those three are within your control: fit a protector from the first night, and measure your slat gaps.
And a guarantee is only worth the company behind it. Four brands reviewed on this site have gone: Eve into administration in 2022, Brook + Wilde liquidated in 2023, and Casper and Leesa out of the UK.
Your statutory rights sit with the retailer, not the manufacturer, for up to six years in England, Wales and Northern Ireland and five in Scotland.
Related reading
Look after it
Is it the base?
How this site works
Nothing here is paid for by a brand. No manufacturer has copy approval, a preview, or the ability to change a score, and where a link earns a commission that never changes a ranking.
Where a brand does not publish a specification, that is stated rather than estimated, because an absent number is itself information. The corrections log and the products I will not recommend page are both public.
Questions people ask
How long should a mattress last?
Eight to twelve years for pocket sprung, seven to ten for dense foam or open coil, and three to five for cheap foam with no published density. Latex runs ten to fifteen.
How do I know if my mattress needs replacing?
Lay a straight edge across it and measure the deepest gap. More than about 25 millimetres and it is finished whatever its age. Waking with pain that eases within half an hour of getting up is the other reliable sign.
Why does a foam mattress stop supporting you without looking worn?
Because foam fails by compression set: the cell walls gradually collapse, so it loses height and support while looking identical. Density predicts how long that takes, and almost no brand publishes it.
Does a slatted base shorten mattress life?
If the gaps exceed about 7.5 centimetres, yes. The mattress sags into the gaps, which is the commonest cause of premature failure and an exclusion in almost every guarantee.
Is a ten year guarantee worth anything?
Only as much as the company behind it. Four brands reviewed here have gone, and your statutory rights sit with the retailer rather than the manufacturer, for up to six years in England, Wales and Northern Ireland.