Which schedule is best for a Direct Mail Campaign?

[Omayra Carroll]

I am putting together my yellow letter direct mailing campaign and I have been told by a couple of professional investors to follow the following schedule: 1st mailing, 2nd mailing within 14 days after the first, then the next 3 months every 30 days with a different yelllow letter each time, after the fifth time to start over. Please give me your opinions on this type of schedule. Is this right? Because I hear on Biggerpockets to do it every 30 days from the start.