You've bought a tv package in the past year. You sponsor local sports on the radio. Your company logo's on a couple of restaurant place mats. The short answer's four or five per week. But there's much more to it.
Effective advertising occurs when the consumer receives a message enough times to change behavior.
If I use Gillette brand, it's going to take a lot of work for Schick to get me to switch. Sellers of Christmas trees better dominate the media during that one busiest week. If an advertiser's goal is to beat the competition, invest in higher frequency. This may be based on your past experience, or competitive factors or on solid research. If newspaper's your medium, and you've been reaching customers with a daily, a weekly and a couple of shoppers, cancel all but the best one or two.