I'd probably look to build the place to be as self-sustaining as possible.

One thing for sure though things don't go up up up forever and appreciation of 10%+ a year isn't sustainable.

I do have abundant experience in sustainable agriculture but I'm completely new to real estate investing and tax liens.

Now, I'm a "why" person so this resonates with me.  

I have seen this over the years in many markets and the default rate for the note buyer is sky high.. not sustainable in my mind.. at least from the investor stand point..  

Ignoring the nuances (that I know we both well understand), does that label terminology resonate with you?

.* There is a self-sustaining requirement for 3/4-plex remaining rents, but, highly recommended!

It's a great sustainable model as leases longer than 30 days are fine.

So, we have the first location selection metric:Significant and sustained population growth, WikipediaRents Persist Throughout Your LifetimeYour rental income will only continue throughout your life if your tenants maintain similar employment as long as you live.

and then you use that money to do another BRRR and in theory you create a self sustaining model.