How Often Should You Replace a Mattress?

The answer everybody quotes is six to eight years, and it is not wrong — the Cleveland Clinic gives the same figure in its guidance on morning back pain, alongside the advice to choose a medium-firm bed. But an age guideline is the weakest tool available for this decision, because mattresses do not fail on a schedule. They fail according to how they were built and how much weight has been sitting on them.

A well-built pocket-coil hybrid under two average-sized sleepers can pass eight years still doing its job. A low-density foam bed under someone heavier can be finished in four. Same calendar, different beds. So this guide is mostly about the tests, with the years as a prompt to run them rather than an answer in itself.

Test 1: look along the surface

The most useful two minutes you can spend on this question. Strip the bed completely — sheets, protector, everything. Crouch beside it until your eye is level with the mattress surface, and look along its length as though sighting down a plank.

You are looking for a hollow where you sleep. A visible dip means the support core has failed under the heaviest part of you, which is the failure that actually matters for a bad back: your hips settle lower than your shoulders and your lumbar curve flattens out for eight hours a night.

If you find one, the mattress is finished. Nothing laid on top of a dip will fix it, because everything laid on top conforms to the shape underneath. That is the single most common wasted purchase in this category, and it is why our mattress-versus-topper guide leads with this same test.

Test 2: the hand test

This one catches a different failure — a mattress that is intact but wrong for you, which is not the same problem and does not need the same solution.

Lie on your back on the bed, relaxed, and slide a flat hand into the gap under the small of your back.

Slides in easily with room to spare: the bed is too firm. Your pelvis and shoulders are being held up while your lumbar curve bridges a gap with nothing under it. A topper genuinely fixes this.

Cannot get your hand in at all: your hips have sunk. Either the bed has always been too soft for you or it has softened with age. If the surface test was clean, a firm topper can help; if it was not, the bed is done.

Snug fit:the support is about right, and your back pain probably has another cause — why you wake up with lower back pain works through the others.

Test 3: check what the mattress is sitting on

The test most people skip, and the one that occasionally saves several hundred dollars. A mattress can be perfectly sound and still sag because the thing underneath it has given way.

Take the mattress off and look. Cracked or bowed slats are common, particularly in the middle of the bed where the load concentrates. Slats spaced more than about three inches apart let a foam mattress settle between them over time. A box spring can lose tension. A platform base can bow.

All of these produce the same dip and the same morning back pain as a failed mattress, and all of them cost a fraction as much to fix. It is genuinely worth five minutes before you spend anything — our guide to fixing a sagging mattress covers the repairs in detail.

Test 4: compare against another bed

The least scientific test and one of the most reliable. How does your back feel after three or four nights somewhere else — a hotel, a relative's spare room, a holiday rental?

People routinely notice they slept better away from home and attribute it to being on holiday. If it happens consistently, across different beds, the variable is your mattress. That comparison is worth more than any age guideline, because it is a direct measurement of the thing you actually care about.

What ages, and how fast

Two components fail on different timelines, and knowing which is which helps you predict rather than react.

Foam softens.Memory foam and polyurethane lose firmness with heat, time and load, and they lose it first where the load is greatest — directly under your pelvis. Density is what determines how fast, and it is almost never published on budget listings. Our budget mattress guide covers the proxies to use when the number is missing.

Coils lose tension more slowly and more evenly.Pocket springs do age, but not seasonally and not in a localized well under one part of you. That is a large part of why we lean toward hybrids for anyone heavier than average — not because coils feel better, but because they hold their support profile for longer.

Pillow-tops settle before the core fails. A quilted comfort layer compresses into a shallow body impression fairly early in a mattress's life. That is normal and is not the same as a sag. The test is still the surface check: an impression in the quilting that does not take the support with it is cosmetic.

Things that do not mean you need a new mattress

It is past its warranty. Warranties describe manufacturing defects, not useful life. A ten-year warranty is not a claim that the bed lasts ten years, nor that it fails at eleven.

It looks stained or tired. Cosmetic. A protector and a wash deal with appearance; support is what you are testing for.

You have had back pain for a while. Not on its own. If the four tests come back clean, your bed is probably not the cause, and buying a new one is an expensive way to find that out. Position, pillow height and simply lying still for eight hours all produce morning back pain in beds that are working fine.

It is only a month old and feels wrong. A new mattress commonly feels wrong for two to four weeks while you adapt. Our break-in guide covers how to tell adjustment from a genuine mismatch before you start a return.

If it is time

Aim for medium-firm, around 6 out of 10 — the randomized Lancet trial found medium-firm outperformed firm for chronic low-back pain, and a systematic review in Sleep Health agreed for spinal alignment. Then make the decisions that determine how long the next bed lasts: coils rather than foam if you are heavier than average, and a listing that actually publishes its certifications, because a maker willing to document one spec tends to document others.

Our pillar roundup covers the field, and the budget page covers what to refuse to compromise on if replacing sooner than you planned.