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5 signs it's time for a new mattress

From sagging to smell to partner complaints, here's how to tell your bed's going bad.

new mattress sad faces
Last updated: 12 June 2024

Getting up on the wrong side of the bed? It could be time for a new mattress.

Shopping for a replacement can be expensive and a pain. But given that we spend eight hours a day in bed (if we're lucky), it's an important investment in a better night's sleep, which we think is priceless.

But how do you know whether it's time to send off your Sealy or can your Koala? How often should you get a new mattress?

"A good mattress lasts an average of eight years, but it does really depend on the quality of its build and materials," says CHOICE's mattress expert, Peter Zaluzny

"When you should replace it is not an exact science, but there are some clues that are good indicators that it's time to move on."

Here are five warning signs to watch out for.

1. It's getting uncomfortable

Tossing and turning all night trying to get comfy is no fun for you (or your partner!) and can lead to fatigue, aches and death stares the next day. 

Hopefully it's just a one-off, but if a rough night's sleep is becoming a regular thing, you may want to slip into something more comfortable, like a new bed altogether.

"Comfort is subjective so you should trust your body," Peter says. "Over time, comfort levels can drop significantly as the mattress starts to wear and loses its support and shape. That's why we test and rate mattresses for comfort as new and after eight years of simulated use – for both male and female body types."

Comfort levels can drop significantly as the mattress starts to wear and loses its support and shape

CHOICE mattress expert, Peter Zaluzny

To do so, our experts mark five aligned spots on the back of dummies that comply to the 5th percentile female (1.55m/55kg) and 95th percentile male (1.9m/100kg) heights and weights then track them with a laser before and after eight years of use (lying on their side and back). We compare the differences to note changes in comfort and support. Learn more about how we test

P95 dummy

Our lab tests use calibrated dummies to consistently assess mattress comfort levels.

Of course, there are also other reasons you might be less comfortable. You might have changed your sleeping style, moved to a hotter or colder house, or now share your bed with a partner. Any of these might have you reconsidering your relationship with your bed and have you looking for a new one.

But if you are experiencing ongoing discomfort, Peter does advise checking with your doctor first. "It may be a health issue and it's worth finding out before you spring for a new mattress," he says.

Mattress damage test

To simulate eight years of use, we use a roller 30,000 times and compare comfort before and after.

2. Your mattress is hard on the nose

Once that new smell fades, your mattress probably won't smell like much – we don't tend to be able to detect our own scent. But if you're finding your mattress a bit whiffy, it could be time to turf it.

One of the many tests we subject mattresses to is the sweat-repellency test. Think that sounds gross? Well, it kind of is. 

Woman peeks out from under a bed sheet

Smell something? It might be time to say bye bye to your old bed.

We place the mattress in a hot room and gradually add moisture over a period of five hours to simulate sweat during sleep. At the end, we measure how much moisture is retained, looking for mattresses that hold onto as little as possible.

The point is this: you don't want any sweat or other icky bodily fluids to stay inside your mattress. If it flows through the mattress – great. If not, it can hang around and create all kinds of unpleasant smells.

If the thought of sleeping on years of accumulated bodily fluid keeps you awake at night, look for the mattresses with the highest sweat-repellency score in our reviews.

3. Your allergies are flaring up 

It's the stuff of nightmares, but over time old mattresses can become a hotbed of dust mites, bacteria, mould and other allergens. If you're sensitive to such things, sharing a bed with them every night can make your allergies and sleep worse. 

Old mattresses can become a hotbed of dust mites, bacteria, mould and other allergens

"Of course, there are other things you should try first before forking out for a new mattress," says Peter. "They need a good clean now and then, like any furniture, as does your room. But a new bed can definitely offer a fresh breath of air."

4. It's getting saggy

Finding it hard to get out of bed? Well, we're not saying that's entirely your mattress's fault, but if you're struggling to get vertical in the mornings, your mattress might be sagging in the middle or at the edges thanks to sprung springs or floppy foam. 

Peter advises rotating your mattress regularly to minimise this happening. "Most manufacturers recommend you rotate a spring mattress every three to six months," he says. "Foam mattresses only need to be rotated once every six months."

Man reaches for alarm clock covering his face

If you're sinking into a saggy mattress, it could be time to spring for a new one.

Flipping your mattress also used to be common practice, but Peter says these days it depends on the specific mattress.

"Foam and spring mattresses with a pillow top don't need to be flipped, as they have designated top and bottom layers," he explains. "However, if they don't have a pillow top, then you can flip them once every six months if you'd like.

"If you're unsure as to whether your mattress has top and bottom layers, check the cross-sections in our reviews, or contact the manufacturer."

Check the sagging score in our mattress reviews to find out which ones stand the test of time. A high score means the mattress held its shape well after eight years of simulated use.

5. You're disturbing your partner

If your other half gets bounced around every time you roll over in bed, you'll probably want to start researching new mattresses pronto, and not just to keep the peace at home. 

This issue can apply if you sleep alone, too. A mattress that makes waves whenever you move is one that's past its use-by date. "If you roll over in the night and then bounce around, that could be a sign of mattress wear," says Peter.

So that you can avoid aftershocks, our experts test mattress stability by dropping a standard weight (17.5kg) onto it to simulate a sleeping person turning over. They then count the number of bounces before it stops. Higher-scoring mattresses bounce less, which means a better night's sleep for everyone.

We care about accuracy. See something that's not quite right in this article? Let us know or read more about fact-checking at CHOICE.

Stock images: Getty, unless otherwise stated.