Product life cycle

A product life cycle is the amount of time a product goes from being
introduced into the market until it's taken off the shelves. There are
four stages in a product's life cycle-introduction, growth, maturity,
and decline. ... Newer, more successful products push older ones out
of the market.
Introduction: This phase generally includes a substantial investment in
advertising and a marketing campaign focused on making consumers aware
of the product and its benefits.
Growth: If the product is successful, it then moves to the growth stage.
This is characterized by growing demand, an increase in production,
and expansion in its availability.
Maturity: This is the most profitable stage, while the costs of producing
and marketing decline.
Decline: A product takes on increased competition as other companies
emulate its success-sometimes with enhancements or lower prices.
The product may lose market share and begin its decline.