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.
Is it time to replace your 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.
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 our2. 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.
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.
See4. 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.
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.
* Stats based on the results of an online survey of 1,029 Which? Connect panel members in February 2026.source https://www.which.co.uk/news/article/signs-your-mattress-needs-replacing-aqDB10w5nPrw