I own it.
It's a pretty simple concept - send multiple letters but keep the list smaller with the most likely buyers.
ie if you do any f2f (or even if you don't) - it's likely that you have a better chance of writing the person who lives 5 miles from your office than you have of writing the people 85 miles from your office.
So, smaller lists. 300 is popular.
Then, mail them not one letter, but several letters over a period of several months sequentially.
ie if I mail 300 (more likely due to proximity) people 6 times, I have a better chance of some calls vs mailing 1800 people one time.
Some areas it works better than others.
And if an agent isn't patient they won't get along with this method. Agents who bug me 2 months into it with "I only got 1 call or 0 or only 2" need to find something else to do.
The majority of my book was built using this method in two different states, so I know it works - but it's small sample sizes and the reality is some months will be better than others, and there are even some areas with just some factors (saturation?) that make it not work at all.
You start mailing 9 months before there birthday to month 3 ? So out of those 300 same people you mail month in month out for 6 months approximately how many total will call you and how many will you close by there 65th birthday ? So how many 300 letters per month will you have going at one time . Once you start it for 6 months won’t you always have 1800 letters a month being mailed every months . What incomes you mailing ?