What can affect the response rate of a Direct Mail offer? It's hard to overstate the point that just about everything can affect response: the mailing list, the creative format, the offer, degree of personalization, and so on. Additional information on a lot of these factors is described in more detail below.
It depends on what you want your campaign to do for you. Ask yourself some questions. Are you selling directly and looking for expense-per-order that provides a certain profit margin? Are you trying to build in-store traffic? Are you attempting to create long-term customer loyalty? Do you want to generate requests for information at a certain expense-per-inquiry? Are you willing to settle for a break-even response rate if it means garnering a list of names that you can continue to sell to in the future? In other words, the measure of your success is in the mastery of your goals.
For one thing, response time will depend on whether you use First-Class Mail or USPS Marketing Mail™ (formerly Standard Mail®). A First-Class mailpieces reach their destinations sooner, and so naturally bring back a faster response. If you chart responses against time elapsed, you will generally see the classic "bell-shaped" curve well-known to statisticians.
Some offers, such as those containing gift catalogs, have obvious seasonal correlation. But even others can show improved performance if mailed at certain times of the year, or in some cases, at specific times of the month. For starters, you can use your existing sales patterns as a barometer of when to mail. Also, you might factor in the timing of your competition's mailings. As is often the case in Direct Mail, some modest experimentation can provide you with guidance. You can send out test mailings at different times to follow seasonal rises and dips for your product or service. And if you have an offer that seemed promising from a creative standpoint, but didn’t not perform as hoped, by all means consider after trying it again during a different period