That's a tough one to answer. Since not everyone sees every page of every issue of the paper, it takes numerous insertions to gain enough frequency with a specific target audience for a message to penetrate. The actual frequency you need will also depend on the complexity of your message and what's being sold.
Kim Gordon is the owner of National Marketing Federation and is a multifaceted marketing expert, speaker, author and media spokesperson. Her latest book is Maximum Marketing, Minimum Dollars