Technically, a mattress can “last” for many decades. We should probably re-frame the question to “How long should a mattress stay comfortable?”, because it’s important to understand that once a mattress has lost it’s comfort, it’s not worth keeping.
A good quality mattress should last for at least 6 years of constant use and can still be comfortable as it approaches the 10 year mark. A poor quality mattress may only be comfortable for a year (if it was ever comfortable in the first place).
So, how do we know how long a mattress is going to last before we purchase it?
The answer is in the foam grades.
Foam is the first thing to wear out in a mattress. Foam can also be the most expensive component in a mattress, if the foam has a high grade. If you can find out the grades of foam that are in the mattress, along with the thickness of each foam layer used then you can guess how long the foams will last before they start to break down and lose their comfort.
We have an article on our site that explains everything that you need to know about foam grades here.
Since high grade foam is expensive, it stands to reason that any mattress that is solid foam should be frightfully expensive if it is going to last for years. A Tempur brand mattress (with higher-grades of foam) usually costs thousands of dollars, as does a solid latex mattress (natural latex is a very high-grade foam).
The logic follows with any online-brand of solid foam mattress that retails for under $700. Clearly, this is going to be constructed with a very low grade foam and I wouldn’t expect this mattress to last for a year.
Innerspring mattresses follow the same principle – it is the foam in the comfort layers that wear out first, so a good quality innerspring mattress should have high grades of foams for it to last for many years. The spring units in innerspring mattresses can last for many decades. If I pulled apart a 50 year old innerspring mattress, the spring unit will probably still be intact but the foams will have long since turned to brittle clumps or even dust.
It is not enough to simply assume that the price of a mattress indicates how long the mattress will last. You absolutely must find out what the grades of foam are in the mattress.
Since the spring unit will last longer than the foams, do not be tricked into thinking that spring unit metrics will affect the longevity in a mattress. Metrics like wire gauge, coil count, spring height etc will only affect the way a mattress feels – they have no bearing on whether the mattress is good quality, good value or will last for years.
Go back to the article: “What’s the best mattress?”