Some people replace a mattress too early because it has a dip. Others keep one for twenty years because it still looks fine. Both can be wrong.
The honest answer to "do I need a new mattress?" is that it depends on how it feels, how it was made and how it has been looked after. Age matters, but it is a prompt to check, not a verdict.
What the guidance says about age
The guidance does not agree, and we will not pretend it does.
- In 2019, the National Bed Federation and the Sleep Council were reported as advising replacement every seven to eight years.
- In August 2026, Which? advised replacing a mattress every eight to 10 years.
Both figures describe mattresses in general, most of them mass-produced. A hand-made mattress with natural fillings and hand side-stitching is built differently and is cared for differently. Treat these numbers as the point at which to look closely, not the date to throw it out.
The signs that matter
Which? lists four signs that a mattress needs replacing. We think they are the right four:
- It is uncomfortable. You wake up stiff, or you sleep better in hotel beds and at friends' houses than in your own.
- It is sagging or sinking in places. A dip that stays after the mattress has been turned and rotated.
- It is more than 10 years old, or shows signs of wear and tear. Torn ticking, a collapsed edge, springs you can feel.
- It is dirty or smelly. Stains and odours that a protector would have prevented, and cleaning will not shift.
To these we would add one more: you and your partner roll towards each other in the night. That usually means the middle has given way.
When a dip is perfectly normal
This is where people get caught out. A mattress filled with natural materials, such as wool, horsehair and cotton, settles as those fibres take your shape. Hypnos says plainly that body impressions are "a normal and natural occurrence" in its mattresses.
Normal settling looks like this:
- It is even. Two shallow, matching impressions where two people sleep.
- It is comfortable. You notice it with your hand, not with your back.
- It responds to care. Turning and rotating the mattress spreads the wear and evens it out.
Failure looks different: a single deep trough, an edge that collapses when you sit on it, or a dip that comes back the night after you turn it.
Age is a prompt to check, not a verdict.
Check the base before you blame the mattress
A tired base can make a good mattress feel worn out. Hypnos warns that putting a new mattress on a worn divan can cause premature wear, and that this would invalidate the guarantee.
Before you replace anything, take the mattress off and look at what is underneath. Broken slats, a sagging divan or a base that creaks and shifts can all be the real problem. Sometimes the right answer is a new base, and sometimes it is both.
What to try first
- Turn and rotate it. If the mattress is turnable, turning it over spreads the wear. If it is a no-turn mattress, rotate it head to foot. We explain both in our guide to turning a mattress.
- Check the protector. A clean protector keeps the mattress fresh and, for some makers, is a condition of the guarantee.
- Do not rely on a topper to fix a sag. A topper changes how the surface feels. It does not repair the support underneath.
If none of that helps, it is time. If the budget is the worry, an ex-display bed is often the most honest way into a better mattress than you expected to afford.
Frequently asked questions
How often should you replace a mattress?
General guidance ranges from seven to eight years (National Bed Federation and Sleep Council, reported in 2019) to eight to 10 years (Which?, 2026). Use it as a prompt to check how the mattress feels and how it is wearing, not as a fixed date.
Are dips in a mattress normal?
In a mattress with natural fillings, shallow and even body impressions are normal. Hypnos describes them as a normal and natural occurrence. A single deep dip, or one that returns straight after turning, is a sign of wear.
Can a mattress topper fix a sagging mattress?
No. A topper changes the feel of the surface, but it cannot restore the support underneath. A sag usually comes back through the topper within weeks.
Not sure whether yours has had its day? Describe it to us on 020 7723 2925, get in touch, or bring your questions to our East Sheen showroom at 215 Upper Richmond Road West, SW14 8QT. We will tell you honestly if a turn and a new base would do the job instead.