Shelf life refers to the length of time that a product, particularly food or pharmaceuticals, remains safe and effective for use. It is determined by various factors, including the type of product, storage conditions, and packaging. Manufacturers often provide a "best by" or "use by" date to indicate when the product is expected to maintain its quality. Understanding shelf life is important for consumers to avoid food waste and ensure safety. Products like canned goods, dairy, and medications can degrade over time, leading to changes in taste, texture, or potency. Proper storage, such as keeping items in a cool, dry place, can help extend shelf life.