Many industries have perishable inventory. Some products just have short natural shelf lives. Products that are organic in nature are often perishable, such as bread, produce, dairy and even health and beauty products. Products requiring refrigeration are usually perishable in one way or another as well, such as pharmaceuticals. COVID-19 vaccines that have a very short shelf life after being taken out of the freezer are a good example. Technology products can be perishable due to either planned or natural obsolescence as the capabilities of devices improve over time. Product cycles that release new models every year have a predictable at-least-partial perishability, from cars to computer chips. Experiential products that require a person to be at a place at a specific time are perishable as well, such as the rounds of golf, hotel nights, transportation and entertainment tickets already mentioned. This article won't focus so much on these, however, as the revenue management techniques for dealing with nonphysical inventories are different. Business-to-business industries have perishable products as well. Some of them are just larger versions of the business-to-consumer problems (like selling food to restaurants), but others are unique, such as advertising slots in a day's newspaper or during a television show.