Life cycles have long been used to understand the evolution of products, businesses, and industries, and are an important tool for investors. A life cycle in business refers to the progression from development to decline of a product, business, or industry. It is a key concept for investors, as understanding life cycles enables them to make more informed decisions about their investments.

Life cycles are distinct for each product, business, or industry and span the period of time from development through maturity to eventual decline and potential discontinuation. The distinct stages of a life cycle may overlap and vary in length, but typically include the following:

1. Development: This is the early stage of a life cycle, when a product or business is still being developed. It is also called the ‘innovation phase’, as the idea of the product or business is refined. At this point, it would be too early for investors to get involved.

2. Introduction into the Market: During the introduction stage, the product or business is launched onto the market and made available to consumers or investors.

3. Growth: This is the period during which the product or business spreads and demand increases.

4. Maturity: As the product or business matures and demand becomes saturated, growth may slow down. Though investors may be discouraged by the maturity of the product or business, it does not necessarily mean it has reached its peak value. In fact, some products or businesses can still be profitable during this stage of the life cycle.

5. Decline: As competitors create similar products and the demand for the product or business begins to fade, it enters the decline stage. This is the last stage before the product or business is eventually discontinued.

The life cycle concept is invaluable to investors as it provides insight into the potential of a product, business, or industry to grow, mature and become profitable over time. It can also provide useful information on when it's best to enter or leave a particular market. Understanding life cycles enables investors to make smarter decisions about their money and can result in more successful investments.