How often I should replace my list

[Nhan Dao]

Hello BP, 

I live in the Bay Area and I don't have enough money to start investing. To have more funding,  I want to start sending yellow letter as a realtor to get more listing to 500 people. 

I want to focus on equity more than 40% and the owners have live there for more than 10 years. 

Or, the second list is divorce. 

Three questions: 

1. Between the two lists, which one would be better?

2. How often do I need to pull a new list?

3. I am planning to send the letter every 2 weeks. Is this frequency too short or too long?

Thank you for your advices!