Direct Mail, how many times?

[Eric Narciso]

I am planning a marketing campaign and am wondering how often do you send to your list?  Say I have a list of 1,000.  Should I mail them weekly, bi-weekly, monthly? For how long -2, 3, 6 months? 

Also, when doing so, do you switch up the mailer?  First a yellow letter, then a post card, then a flyer, then what?  

How often should I be getting a new list?  I can't keep mailing to the same 1,000 people for a year, right?