I have never held a mortgage 15 years (or even 12.5 years) and I have had quite a few mortgages.I claim that it is better to have the negative cash flow and use the $450k to achieve a return in excess of the 6%.  

Sometimes you can find a large enough company that you can sub everything out to them and get paid on a commission or flat fee basis, or you can get the property platted and sell it that way.

I never go off of a flat percentage on anything, I analyze the costs to get to a specific return I target and analyze the risk that is involved. 70% may be an initial metric to see if it is even worth pursuing, but every deal should be evaluated independently based on costs, time and risk involved.

So while I have family nearby I want to minimize excess wear and tear because 1.

We will quickly correct the excess spending, and fill the vacant units with quality residents.

A market like Boston has a long track record of appreciation in excess of inflation/cpi.  

I personally don't charge for small holes and touch-ups unless they are grossly excessive, but I would charge for removing the tape/adhesive.

Brokers, loan officers, and underwriters flat out get things wrong sometimes.

Thus, I'd expect something like the following for the next three years for US rents: 1) 2025 will not see much national rent growth as we continue to deliver so much supply that prices remain largely flat.

After all, the Earth is flat in some forums.