General guideline: It is recommended to use up most standard cream foundations within 6 to 12 months of opening; some products feature a "12M" symbol, indicating a safe usage period of 12 months post-opening.
Variations by type: Oil-based or water-based cream foundations can typically remain stable for 1 to 2 years when stored correctly, though improper storage will significantly shorten their shelf life.
Factors accelerating spoilage: Exposure to high heat or humidity, scooping the product with unwashed hands, or failing to tightly close the lid after use can cause premature signs of spoilage, such as oil-water separation, unpleasant odors, or clumping.
