New unit: 4-unit multi family in which 3 units (with existing tenants that will carry over from seller) will remain investment; I will move into (currently empty) 4th unit AND USE as primary residence with primary mortgage.

Gross profit is interesting because it appears to just be the difference in his acquisition and sales price and fails to take into account the other obvious cost of running that business which includes, again according to him, the cost of over 26,000 letter print, mail, post, and the cost of the lists needed to create a mailer of that size. 

I know there has been a lot of posts here about not over complicating things but I get nervous when I hear it just takes one case to wipe out the entire wealth :)).

Your second question is in line with what I mentioned above you need to test, test, and continue to test.

As long as I can get my target numbers without being pet friendly that is what I will continue to do. 

Over the years, we’ve built relationships, closed countless deals, grown businesses with fellow BP members, and helped others get started—all from meeting people here on the forums.The Lehigh Valley is a fantastic market to kick off your journey.

Over time, I found a circle of mentors who believed in me and were willing to share their knowledge.

Paid $26k, sold for $80k over 30 years.

I can see the misunderstanding here, but I still don't think the strategy will bear fruit over time.

This is relevant for multiple reasons 1) appreciation is where the real wealth is generated in RE 2) real estate has tax advantages over cash flow 3) in CA property tax increase is capped.