How long does a mattress last, and when should you replace it?

The short answer: There is no reliable fixed number. How long a mattress lasts depends on its materials — especially the density of its foams, which brands rarely publish — on the weight it carries, on the base under it, and on how it is looked after. Replace it when it shows the signs: dips or body impressions you can see or feel, waking stiff or sore in a way that eases during the day, sleeping better in other beds, sagging edges, noisy springs, or worse allergies. The warranty length is not a promise of how long it will last.

Why there is no single number

You will see lifespans quoted for mattresses everywhere. They are averages at best, and they hide most of what decides the answer:

• Materials. Higher-density foams keep their shape longer than low-density ones. Pocket springs and latex tend to outlast soft comfort foams. The comfort layer at the top usually wears first.
• Density is rarely published. Without it, two mattresses that look identical on paper can age very differently.
• Load. A mattress shared by two heavier adults works harder than one used by a single light sleeper.
• Use. A guest-room mattress used a few weeks a year will outlast the one you sleep on every night.
• The base and care. A sagging base, no protector, and never rotating all shorten a mattress’s useful life.

So the useful question is not “how old is it?” but “is it still doing its job?”

Signs it is time

• Visible dips or body impressions. Some settling where you lie is normal, especially in the first months. A hollow you roll into, or one that stays when you get up, is not.
• You wake stiff or sore, and it eases after you have been up for a while.
• You sleep better elsewhere — in a hotel, a guest bed, on the couch.
• The edges have gone soft, and you feel as if you might roll off.
• The springs creak, ping or poke through.
• You can feel your partner move far more than you used to.
• Your allergies are worse in bed. Old mattresses collect dust mite allergen and skin cells, particularly without a protector.
• Your body has changed. A weight change, pregnancy, an injury or a new back problem can mean a mattress that suited you no longer does, even if it is in good condition.

One sign on its own may not mean much. Two or three together usually do.

How to measure a dip

Strip the bed, then lay something straight and rigid — a long level, a broom handle or a taut piece of string — across the mattress where you sleep. Measure the deepest gap between it and the surface.

Warranties define the depth at which a dip counts as a defect, and only dips on a properly supported mattress usually count. If yours is within the warranty period and the dip is deeper than that figure, it may be a claim. What a mattress warranty covers explains how those claims work, and why the warranty length is not the same thing as a lifespan.

Is it the mattress or the base?

Before you replace a mattress, check what it is sitting on. Broken or bowed slats, a missing centre leg, or a sagging ensemble will produce a dip in a perfectly good mattress. Try the mattress on the floor for a night or two: if the dip disappears and you sleep better, the base is the problem. Our bed base guide goes through what to check.

Making a mattress last

• Use a protector from day one. It keeps out sweat and spills and keeps the warranty intact. See our protector guide.
• Rotate it if the maker says to. Turning a mattress head to foot spreads the wear. Many one-sided mattresses should be rotated but not flipped; check the instructions.
• Keep it on a sound base that meets the warranty conditions.
• Avoid sitting in the same spot on the edge every day, and don’t let anyone jump on it.
• Keep it dry and aired. Strip the bed now and then and let it breathe. How to clean a mattress covers the routine.

When it is time to go

Once you have decided, a few options for the old one:

• Removal on delivery. Many retailers will take the old mattress away when they deliver the new one, often for a fee.
• Council collection. Many councils run hard-rubbish collections or accept mattresses at transfer stations, sometimes for a fee.
• Recycling. Mattress recyclers operate in many parts of Australia, recovering steel, foam and timber. Your council can usually point you to one.
• Donation. Only if it is genuinely clean and in good condition — many charities no longer accept used mattresses, so ask first.

When choosing the replacement, how to choose a mattress walks through it step by step.

Common questions

How often should you replace a mattress?
When it stops doing its job, not on a set schedule. Watch for dips, morning stiffness, sagging edges and sleeping better in other beds.

Does a 10-year warranty mean the mattress lasts 10 years?
No. A warranty covers manufacturing defects as the warranty defines them. Normal softening and comfort changes are usually excluded.

Is some sagging normal?
Some settling where you sleep is normal, especially in the early months. A dip deep enough to roll into, or one that keeps getting worse, is not.

Can I fix a sagging mattress?
Rotating it can even out wear, and fixing the base can remove a dip that was never the mattress’s fault. A mattress whose own materials have broken down cannot really be restored.