@Cornelius Charles-
Remember that time and circumstances change all things, so when it comes to absentee owners you need to commit to mailing to them until the house is sold.The seller that isn't motivated this month (or even this year) may have a "life event" that changes that like a divorce, a death or something else. Suddenly they are a motivated seller.
I have bought houses after 2 or 3 years. So for the house I bought after 3 years that was 36 stamps and 36 pieces of paper and 36 envelopes. You can do the math. I made $12,000 off that house. Remember 80-85% of your deals will come at or beyond the 5th mailing. Often it's the last guy standing. Get a new AO list every 6 months or so.
Probates will generally be sold in 15 to 18 months in my area. I mail to them until the property is sold. New people die each month and they get added to the list, others come off.
You have to create systems and use a calendar to chart when mailings are due. You also need some type of database. A lot of people use Podio today which is free.
The average return on direct mail is about 2% these days so on 1000 mailers you could expect about 20 motivated sellers to cal you. On average is you need to talk to about 20 sellers to get a deal. So for each 1000 mailers you might expect to get a deal. Now in some areas that number is closer to a 1% return on direct mail, so you would need to be doing about 2000 mail pieces a month to get 20 calls. Every area is different. But even if you spend $1000 to make $10,000 that is still a great return.
So my question is, why would you stop? The whole point is to build momentum. Direct mail takes a while to get that momentum.
You have to get someone to look each property up on the tax assessor's site to see if it's sold. In a best case world you would do that quarterly.
This process is simple, but no one ever said it was easy. I mail every person every month until the house is sold.