How long does paint last?
Unopened latex paint stored somewhere cool and dry commonly stays usable for years; once opened, it depends entirely on how well it was resealed. Paint that has frozen, separated permanently, or smells sour is finished, and no amount of stirring recovers it.
How to tell whether a tin is still usable
Open the tin and stir it thoroughly first — separation on its own is normal and reverses with a few minutes of proper mixing. What does not reverse is a rancid or sour smell, which means bacterial growth, or a lumpy, stringy, curdled texture that will not blend back together.
Freezing is the other killer. Latex paint that has frozen and thawed may look fine and still fail to form a proper film, so paint stored in an unheated garage through a cold winter is a genuine risk.
To store paint well, seal the lid properly by tapping it down around the rim rather than hammering the centre, and keep the tin somewhere that never freezes and never bakes. Storing it upside down is a widely repeated tip that creates a seal at the lid — it works, but only if the lid is genuinely tight.
Test any doubtful tin on a scrap of card before committing it to a wall. If it goes on smooth and dries to an even film, it is fine. If it is gritty or dries patchy, dispose of it and buy fresh — the labour of repainting a failed wall costs far more than a tin of paint.
How we sourced this
This answer is composed from our knowledge base, which holds only what a regulator, a standards body or a manufacturer supports. The sources behind it are listed below with the date we accessed each one. If a claim on this page has no source under it, that is a bug — tell us and we will fix it.
Where a figure is product-specific — coverage, dry time, recoat time, temperature limits — we point you at the manufacturer's technical data sheet rather than printing a general number as though it were a specification. That distinction is the most common error in this trade, and it is the one that costs people a repaint.
Common mistakes
- Throwing out paint that has merely separated. Separation is normal and stirs back in.
- Keeping paint in an unheated garage. One freeze-thaw cycle can ruin latex that still looks fine.
- Hammering the lid down in the centre, which distorts it and breaks the seal.
- Using a doubtful tin straight onto a wall instead of testing it on card first.
Related questions
Sources
- Sherwin-Williams. Product technical data sheets (accessed 2026-08-17).
- US Environmental Protection Agency. Household Hazardous Waste (accessed 2026-08-17).