Should I Replace My Mattress?
Most people asking this question do not need a new mattress. They need a slat, a topper, or a warranty claim they did not know they owned. Start with the symptom and work down to the answer.
Replace, topper or foundation?
Have you looked underneath the bed?
Every diagnosis starts here, because a broken slat or a missing centre support produces a hollow that looks identical from on top — and because every warranty excludes sag caused by an unsupportive base.
This diagnostic is general guidance for mattress owners, not medical advice. Persistent pain, numbness or tingling is worth discussing with a clinician regardless of what your mattress is doing.
Start from the symptom
Every guide in this hub answers one complaint and hands you back to the decision above.
The five-minute self-check
- Look underneath. Torch, floor, five minutes. Cracked or bowed slats, a slat out of its bracket, a missing centre support leg on a queen or larger, or a box spring that dips when you press it.
- Strip it bare and wait. Leave the mattress uncovered for a few hours with nothing on it. This is what separates a body impression from a sag.
- Measure with a straight edge. Across the width, over the deepest point, no weight on the bed. Photograph the tape measure in place.
- Find your threshold. Over 0.75" at Tempur-Pedic, over 1" at Purple and Casper, over 1.5" at Nectar, DreamCloud, Helix, Brooklyn Bedding and Avocado.
- Check the clock. Sleep trials close on a date and cover comfort; warranties run for years and cover defects. Know which one you are inside.
Frequently asked questions
How do I know if my mattress needs replacing?
Strip it bare, leave it a few hours, then lay a straight edge across the deepest hollow and measure down with no weight on the bed. A hollow that recovers is a normal body impression. A hollow you can still measure is sagging — check it against your brand's warranty threshold before assuming you have to buy anything.
Should I buy a topper or a new mattress?
A topper is the right answer when the mattress is structurally sound but too firm, or when the surface has softened without collapsing. It is the wrong answer for a measurable sag, because a topper takes the shape of whatever is under it and a soft one deepens the hollow.
Can a new bed frame fix a sagging mattress?
It can fix a hollow caused by a broken slat, a missing centre support or a tired box spring, which is far more common than people expect. It cannot lift a support core that has already collapsed. Check underneath before spending anything else — it is also the cheapest fix available.
Is my back pain caused by my mattress?
Pain that is worst on waking and eases within an hour of getting up points at the sleep surface. Pain that persists through the day, wakes you at night regardless of position, or comes with numbness, tingling or weakness is not a mattress question and is worth raising with a clinician.
Does a warranty cover a mattress that is too soft for me?
No. Every mattress warranty excludes comfort and normal softening — they cover manufacturing defects only. A firmness mismatch is handled by the sleep trial, which closes on a date, so check your window before doing anything else.