The main stages of the product life cycle are:

• Introduction – researching, developing and then launching the product
• Growth – when sales are increasing at their fastest rate
• Maturity – sales are near their highest, but the rate of growth is slowing down, e.g. new competitors in market or saturation
• Decline – final stage of the cycle, when sales begin to fall

This can be illustrated by looking at the sales during the time period of the product. A branded good can enjoy continuous growth, such as Microsoft, because the product is being constantly improved and advertised, and maintains a strong brand loyalty.

Extension strategies extend the life of the product before it goes into decline. Again businesses use marketing techniques to improve sales. Examples of the techniques are:

• Advertising – try to gain a new audience or remind the current audience
• Price reduction – more attractive to customers
• Adding value – add new features to the current product, e.g. video messaging on mobile phones
• Explore new markets – try selling abroad
• New packaging – brightening up old packaging, or subtle changes such as putting crisps in foil packets or Seventies music compilations