If you send out mailers without making that calculation you are winging it.You mostly hear from people that are making deals from DMM but you never hear from  the vast majority of people that got NO WHERE using DMM because no one like to brag about a failure.The only way you can reliably make money from DMM is if you spend a fortune on it ... obviously because the open rate is so low.If you are a beginner and it sounds like you are, ask other people how reliably successful the majority of BP has been with DMM.Again the only people boasting DMM are those that have no clue what it is like to try a real marketing system, like facebook ads or PPC or SEO.Everyone screams DMM, but NO ONE shares their numbers.Show me the numbers.