If you've got a budget to mail 5000 post cards is it better to mail to mail to 5000 prospects  -or-  should you mail to 1000 prospects 5 times?

If you're selling pizza, and you want to sell as many as you can in a short period of time, mail the 5000 all at once. Many prospects are going to order a pizza within the next week or so.

If you're a travel agent, however you would want to mail to people at a time when your prospects are planning a trip. How do you know when that is? You don't! So you have to mail regularly. In this case it might be better to mail to 1000 prospects 5 times.

When they're ready to travel, you're mailing is either in their mailbox or in their recent memory. It's called creating a "Top Of Mind Awareness".  

Realtors have the same challenge. They don't know when someone is going to sell their home, but when the time comes, they want the seller to remember their name! 

Another advantage to multiple mailings is that it allows you to test different offers or messages. Monitoring response and fine tuning your postcard will result in improved response rates.