As you mentioned, it might be difficult timing the sales of each of properties where you can achieve a combined exchange (multiple properties into 1 property / or a few properties).Just a quick note that may be helpful - I work with a group of investors that can help with a combined exchange into a single property and will buy it back once you've found a replacement propertie(s) as the final destination for your capital.

The primary requirement is that the expected rent would cover the mortgage on the home - and that expected rent is typically determined by a combination of the appraiser and some service like airdna (a site which determines fair market rent).

They are either a combination of a Maintenance/Tenant Management business or Accounting/Real Estate sales/Tenant management service. 

Don't forget to account for the cost of the appraisal or any other vendors...an appraisal and survey will over $1000 combined, for example. 

So call it $12k/mo combined was our best year ever.

The other reason tax bills get stalled in Congress is that most bills combine multiple unrelated measures, usually serving various special interests.

As to Grant Cardone, you have to have capital to do a bigger deals... and syndications is one way you can do that (which as I understand it is the deal that Grant pitches)... combine  your money with others to do the big deal... but at the end of the day, you own $20,000 worth of a $10 million deal if you put in $20,000.  

Real estate investing can be a combination of cash flow or appreciation.  

There are buyers that prefer any combination.

There was a glut in wineries not long back when The Australian dollar was high and people who once couldn't get enough of Australian wine suddenly turned back to relatively cheaper and more fancy sounding French and Italian plonk, combined with the change in regulation in the Chinese wine market that killed it as a business drink.