We can see how the product life cycle works by looking at the introduction of instant coffee. When it was introduced, most people did not like it as well as "regular" coffee, and it took several years to gain general acceptance (introduction stage). At one point, though, instant coffee grew rapidly in popularity, and many brands were introduction (stage of rapid growth). After a while, people became attached to one brand and sales leveled off (stage of maturity). Sales went into a slight decline (衰退) when freeze-dried coffees were introduced ( stage of decline).
　　The importance of the product life cycle to marketers is this: Different stages in the product life cycle call for different strategies. The goal is to extend product life so that sales and profits do not decline. One strategy is called market modification. It means that marketing managers look for new users and marked sections: Did you know, for example, that the backpacks that so many students carry today were originally designed for the military?
　　Market modification also means searching for increased usage among present customers or going for a different market, such as senior citizens. A marketer may reposition the product to appeal to new market sections.
　　Another product extension strategy is called product modification. It involves changing product quality, features, or style to attract new users or more usage from present users. American auto-manufacturers are using quality improvement as one way to recapture world market. Note, also, how auto-manufacturers once changed styles dramatically from year to year to keep demand from falling.