A familiar definition of product life cycle is the duration when a product is first introduced to customers until it is removed from the market. This definition is generally used by businesses and marketing teams and is divided into 4 broad stages: product introduction, growth, maturity, and decline. This is a customer centric definition, and pegs product maturation to sales; first sales are expected to grow after introduction, then sales will plateau and eventually drop off, signaling the decline of the product. This model is very useful for companies that acquire assets to resale, or do not manufacture themselves. For some business cases this model is an incomplete representation of their products' life cycles.
The Typical 4 stage product life cycle:
1. Product introduction to market
2. Product sales growth
3. Product sales maturation or plateau
4. Product sales decline and removal from market
With the inclusion of engineering and product design' contributions, an additional 'development' stage is inserted before the 'introduction to market' stage. The development stage has been heavily expanded on by the software industry due to their needs.
Software companies have cycled through several approaches to development, beginning with the waterfall approach that models the development process in phases: definition, design, development, testing, and eventually final product deployment. Waterfall has a disadvantage of being product focused, whereas the newer Agile method is customer centric. Notoriously, waterfall products are completed without much customer input, deploying only after significant development time.
The adoption of a customer centric approach, and the short development cycles espoused by Agile, allow companies to incorporate customer feedback into their designs more readily. This has been a boon for SaaS products, which have turned product life cycle into a continuous customer feedback loop, incorporating new insights and rolling out updated versions so effortlessly they can make improvements within hours of discovery.
The 5-stage product life cycle accounts for product development:
There are other considerations, such as with big-ticket assets requiring long-term service components intent on keeping those assets operational over years, even decades. The product life cycle stages are expanded while remaining within the same "development to disposal" model. During the life of the asset, maintenance and upgrade stages may be inserted, with the expectation that the product will decline when its useful life ends, rather than when the market is done with it. For example, the market may replace fridges with smart fridges, but the nature of cargo ships prefers them to be maintained until they stop floating.