Latex paints in unopened containers that are well sealed can last up to a decade and a half. On the other hand, latex paints that have been opened can stay without spoiling for two years.
The period of time paint can remain viable is determined by whether the paint is oil- or latex-based. Storage conditions are also another determining factor in estimating the average shelf life of paint.
Latex paints tend to last longer than the oil-based paints. Latex paint has a unique chemical composition that prevents growth of bacteria as well as maintaining the thickness of the paint by preventing it from separating. To ensure that latex paint lasts for over a decade, it should be stored in a tightly sealed can free from any contaminant.