1. Direct mail has higher costs upfront but provides better reach and response rates than email, SMS, or telecalling. 2. While email, SMS, and calls have lower costs, they have much lower open and response rates and cannot reach many high-net-worth individuals who use do-not-disturb services. 3. Direct mail has the advantage of no do-not-disturb issues, cuts through clutter, and can be read by multiple people, making it more cost-effective than other media despite the higher upfront costs.