Nail polish can go bad, but with proper storage it lasts an extremely long time. Manufacturers rarely list an expiration date on nail polish, so monitoring the polish's texture is necessary to determine if it has gone bad.
Polish reacts to changes in heat and sunlight, as ingredients separate and evaporate. Polishes that undergo frequent temperature changes or that are left in open sunlight thus may become full of clumps. In some cases, stirring helps restore the proper texture, but sometimes the polish is ruined. Beautylish recommends that Nail polish be stored in a cool, dark place with a consistent temperature to ensure it lasts for many years.