the length of time that a product remains in good condition after it is made and can be sold （包装食品的）保存限期◆Canned food usually has a shelf life of two years or more. 罐头食品的保质期通常为两年或更长时间。➡ see note at best-before date
the length of time that people will buy a product after it is first available 货架存放期◆Software packages usually have a shelf life of around 18 months before they need updating. 软件包在升级前通常有约 18 个月的货架期。