The specifics of adding additional units vary WILDLY across cities, towns, and counties.This strategy (buying and further developing with additional units) has been my specialty since 2011 - I've learned more about the complexities than I ever expected or wanted to, even with the loosened ordinances we have in place here now. 

I would like to have some sort of mentor that I can help in exchange for knowledge, and somebody that I can just ask questions to and talk with.I have been seeing across the entire city and suburbs these small road signs that advertise "Real Estate Investor Seeks Apprentice" they are all different, and some of them even make wild promises like "make $10,000 a week while you learn to invest!"

I also know what I pay for insurance so when they give their estimate I can know if it's makes (ballpark) sense or, again, if it's wildly high or wildly low.  

They can vary wildly depending on the age of the property, who pays utilities, type of tenants, and more.  

I watched my stock market account shoot wildly up and down, while this property consistently handed me checks for $1,150 each month... the rental property was a better performer.

But as you know it became a fad and grew like wild fire and the deals were subscribing so fast that there was no way the investors could have done a minute of Due diligence and it played out EXACTLY like your describing..

Many of us have a baseline that we don't fall below, simply because "there's always someone that wants to buy a home" and we've established ourselves over the course of years, but the variance above that baseline is wild and unstable.

It's the wild wild west.

- Back in the wild, wild west days of lenders and real estate.

When you dig in, they can be wildly inaccurate because there are variables they can never consider, like size of bedrooms, layout, view from the living room window, cranky neighbor with yappy dogs net door, etc.