A decent rule of thumb for estimating the vacancy component of the 50% is 8.33% (one month out of 12).

I'm confused on this b/c I am missing the mktg component of the biz card right now, but just don't want to be handing out my cell phone # indirectly to anybody.

Positive monthly cash flow is only one component of your total return.  

I know time and starting early is the best component for financial success, especially with the appreciation factor in real estate.

The key component is that the HELOC is based off of the average daily balance and the mortgage is amortized.  

I left out a key component: This stat was for properties listed under $80,000.

House components are primarily (Especially modern houses) built to last between 15-25 years.

And your generally dealing with a home that is 20 years old or less.. stucco  tile roof  newer components etc no freeze thaw issues.. easy desert landscaping. 

@Tim Herriage has big meetup with both components monthly at the Addison Conf Center.  

Depending on the asset it might be best for a seller to use the PM company just to manage and a transaction broker for the sale and marketing of their property.I am in the commercial brokerage and investor component you mentioned.