A Typical Product Lifecycle
Most inventions are in and out of the market within a few years. Years 1 to 2-1/2 are the introductory years. You take your product through the idea and development stage while you check out the commercial market, apply for legal protection, and try to obtain funds.
At about year 2-1/2, the product enters into the market and sales start. They peak at about year 5. During year 6, you must cope with new competition and competitors and by year 7, the sales are in decline. Remember, although your patent life is for as much as 20 years, the market life is quite different and nearly always shorter.