When properly sealed in a container, oil-based paint boasts the longest shelf life of any type of paint. A can that's been opened and properly resealed may easily last a decade in storage, while unopened paint can last up to 15 years.

How long does paint last if never opened?

Unopened cans of paint last for years when stored correctly. Unused latex and water-based acrylic paints last up to 10 years, and the shelf life of alkyd and oil-based can be as long as 15 years.

How can you tell if paint is bad?

Rancid- or Sour-Smelling Paint

After the lid is opened, some paint might have a sharp smell: rancid, foul, or sour. Other paint might smell like mold or mildew. If the smelly paint is applied, the smell may lessen but not disappear.