All products go through a natural lifecycle, and so should your promotional mix.

Introductory Stage: A product first hits the market.

Growth Stage: A product is making money and expanding its market share.

Maturity Stage: Most everyone knows about the product.

Declining Stage: Consumers start looking for the next big thing. It is important to plot where you are on this lifecycle. If you're in the Introductory and Growth Stages, you should rely more heavily on promotional channels like public relations and promotions that reach out to consumers and teach them about your product's features and benefits.

On the opposite end of the continuum are the Maturity and Declining Stages, when your goal changes from 'reach and teach'  to 'reach and remind'. You need to tap people on the shoulder and say, "Don't forget about us." Advertising and sponsorships are ideal channels at these stages.