When to Replace Your Mattress (And When Not To)
"Replace your mattress every eight years" comes from the industry that sells mattresses. Some last six, some last twenty. Test yours instead of counting.
The four tests
1. The straight edge
Strip the bed. Lay a broom handle or a spirit level across the mattress, from side to side, where you sleep. Any daylight under it in the middle is a sag. More than about 3 cm and the mattress is done — that is also the threshold most guarantees in the trade use.
2. The other-bed test
Sleep somewhere else for three nights — a hotel, a spare room, a relative's house. If the ache goes away and comes back when you get home, it is the bed. If it comes with you, it is not.
3. The edge test
Sit on the edge where you get in and out. If you slide off, or the edge collapses much further than the middle does, the border support has gone. On a sprung mattress that usually means the perimeter springs have failed and there is no repairing it.
4. The noise test
A sprung mattress that has started creaking or twanging has broken or unseated springs. That gets worse, never better.
When it is not the mattress
Three things get blamed on the mattress regularly and are not the mattress.
- The base. Slats sag before mattresses do, and a slat that has dropped or snapped puts a dip in a perfectly good mattress. Take the mattress off and look. Gaps wider than 7 cm between slats will also ruin a mattress over a few years — and void the guarantee while doing it.
- The pillow. Neck and upper-shoulder pain is far more often the pillow than the bed. A pillow costs a fortieth of a mattress; change it first.
- Firmness that was always wrong. If it has never been comfortable, it was not the right mattress on day one and it has not degraded — you bought the wrong firmness. A topper can rescue a too-firm mattress. Nothing rescues a too-soft one.
What actually shortens a mattress's life
- Never rotating it. Head to foot, every three months for the first year, then twice a year. Most modern mattresses are no-turn but all of them should be rotated.
- Sitting on the same edge every day. The edge is the least supported part of any mattress. Getting dressed in the same spot for years puts a permanent dip there.
- A base that does not ventilate. Solid platforms trap moisture under the mattress. Stand it on its side for an hour when you change the sheets, a few times a year.
- No protector. Not for the life of the mattress — for the guarantee. A stain is the most common reason a claim is refused, and a protector removes the argument.
Realistic lifespans
| Build | Typical working life |
|---|---|
| Open coil | 6–8 years |
| Memory foam over springs | 8–10 years |
| Pocket sprung with foam comfort layer | 10–12 years |
| Latex | 12–15 years |
| Hand-tufted natural fillings | 15–20 years |
These are working lives, not guarantee periods. Our guarantees run 5 to 10 years depending on the range, and the number is on every product page.
Getting rid of the old one
Around seven million mattresses a year reach the end of their life in the UK and most still go to landfill or incineration, largely because separating steel from foam from textile is laborious. Local authority bulky-waste collection is the cheapest route; most councils charge a small fee. If we are delivering, we will take the old one away and hand it to a licensed recycler.
Common questions
Can a sagging mattress be repaired?
No. The sag is compressed foam or collapsed springs and neither recovers.
Is a board under the mattress a fix?
It stops a failing base from making things worse. It does nothing for a failing mattress and it removes the ventilation underneath, so use it as a temporary measure only.
My mattress is fine but my partner's side has gone.
Common, and it means the mattress is at end of life — you are sleeping on the half that has had less load. Two zip-and-link singles are the usual answer for couples with very different weights.