How are consumer products classified by durability and buying effort?

"To help them define target markets, marketers have devised product categories. Products that are bought by the end user are called consumer products. They include electric razors, sandwiches, cars, stereos, magazines, and houses. Consumer products that get used up, such as Nexxus shampoo and Lay’s potato chips, are called consumer nondurables. Those that last for a long time, such as Whirlpool washing machines and Apple computers, are consumer durables. Another way to classify consumer products is by the amount of effort consumers are willing to make to acquire them. The four major categories of consumer products are unsought products, convenience products, shopping products, and specialty products, as summarized in Table"