Water-based acrylic and latex paints can stay good for up to 10 years if never opened and kept from freezing. Leftover paints that have been opened should be closed up tightly, stored in a cool, dry place and used within two years.

How can you tell if paint has gone 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.

Does interior paint go bad?

See how almost two dozen lines of paint perform in our interior paint ratings. Leftover latex paint can last years, even a decade, or go bad in mere months. “When the paint can is bulging or the lid is puffed up, you know it’s bad,” says Enrique de Paz, who oversees Consumer Reports’ paint tests.