4 warning signs your mattress needs replacing
A veteran consumer advocate with over two decades of rigorous product-testing experience, Lisa leads our mattress category and joined the home energy team, helping bring clear, actionable advice to consumers.
How long have you been sleeping on your mattress? If you’re like most people, you probably can’t even remember when you bought it, let alone know when you should replace it.
If you're paying hundreds for a mattress, you'd expect it to last a few years. We recommend you replace your mattress every eight to 10 years, but nearly half of the Which? members we asked in a recent survey* kept theirs for longer.
Read on for signs you need to replace your mattress and our expert advice on extending the life of your new one.
Head to our mattress reviews to find the perfect mattress for you.
Is it time to replace your mattress?
Our survey results really surprised me because decent sleep is such an important part of our lives. It seems that plenty of people are sleeping on old mattresses that are way past their best, not to mention harbouring a whole host of bugs and bacteria. If any of the following points ring true for you, it might be time to invest in a new mattress.
1. It’s uncomfortable
Comfort is a big deal when it comes to getting a decent night's sleep. In our mattress survey*, comfort was cited as one of the main reasons Which? members ditched their old mattress. One third bought a new mattress because it felt comfortable when trying it out in the shop.
Comfort is subjective, though, which is why it's so hard to pin down one mattress that suits everyone. What works for you may not work for someone else.
Our guide to the best mattress brands reveals the brands Which? members say make the most comfortable mattresses.
To inform our reviews, we put each mattress through body support tests. We also measure pressure distribution. These tests are designed to reveal if you'll sink into a mattress in one spot more than another – this could aggravate existing back issues or cause problems in other places.
If you already have back pain, or any other aches and pains, a new mattress won't solve the underlying issue – you should see a medical professional instead.
Suspect an old, saggy mattress is worsening your back pain? See our best mattresses for back pain
2. It’s sagging or sinking in places
Are you sleeping in a dip? As a mattress ages, its layers can compress, causing it to sag or soften. However, you may not notice it as you become used to sleeping on it over the years.
Our durability tests mimic eight to 10 years of use by repeatedly rolling over mattresses with a large, heavy roller to compress them. We run our body support tests before and afterwards. The resulting data reveals how compressed the mattress becomes and highlights any reduction in body support for the three main sleeping positions (front, side and back).
Be aware that if your old mattress is soft or sagging, it can affect how you feel about your new one - you could find a new mattress feels a lot firmer than you're used to.
Find out more about our rigorous testing processes in how we test mattresses.
3. It’s more than 10 years old, or there are signs of wear and tear
The NHS recommends seven to nine hours of sleep per night; assuming 10 years of use and seven hours sleep a night, this equals around 22,550 hours of use for your poor mattress.
That's not taking into account any other use, such as working from bed, or when you're ill or recovering from an operation where you are likely to be in bed for longer periods.
If you notice any damage to the foam, springs poking out or stitching coming loose, it's probably time to consider a replacement.
See best mattresses for top tips on how to buy.
4. It’s dirty or smelly
The National Bed Federation says that by the time your mattress is seven years old, it could have absorbed the equivalent of a bathful of body moisture, depending on how much you sweat each night.
It will also accumulate around 450g of dead skin in that time, which isn't ideal if you are sensitive to dust mites.
Plus, spills and stains can accumulate over time.
That means an old mattress can be a pretty grim place to sleep.
Head over to our guide on how to clean a mattress for step-by-step advice.
How to make a new mattress last longer
There are plenty of things you can do to help make your mattress last longer.
Reading the care instructions is a good place to start – otherwise you could inadvertently void the mattress warranty or cause damage, by using it incorrectly or not looking after the mattress as recommended.
Regular cleaning will help keep it in good condition, and airing your mattress regularly as well as vacuuming it will help stop moisture lingering and dust accumulating.
Avoiding eating and drinking in bed and stopping pets or kids jumping about on your mattress will all help to keep it in good condition.
You could also invest in a mattress protector or a mattress topper.
Find out how to dispose of your old mattress in an environmentally responsible way.
* Stats based on the results of an online survey of 1,029 Which? Connect panel members in February 2026.
This article uses insights from the Which? Connect panel, collected from research activities with our members. Find out how to get involved
