The product lifecycle is the collective stages that a product goes through from its conception and design through to its ultimate disposal.
In manufacturing, the lifecycle stages are generally categorized as beginning-of-life (BOL), middle-of-life (MOL) and end-of-life (EOL). The beginning-of-life stage encompasses everything to do with product development: the design, creation, testing and initial marketing of a new product.
If a product is successful, the middle-of-life stage is of longer duration than the other stages. MOL is where the majority of marketing and sales endeavors are concentrated. In a marketing context, the product lifecycle is usually considered to begin with initial marketing and finish with the decline in sales. So, essentially, the marketing product lifecycle is roughly equivalent to the middle-of-life segment of the manufacturing-centric product lifecycle.
The product end-of-life is the stage where a product is discontinued. Depending on the type of product, EOL may be planned and scheduled. However, a product's EOL is more often the result of a decline in sales or the release of a new product that replaces it. A comprehensive EOL strategy includes plans for disposal of the product or its components.