I live in North Alabama and currently work as a medical professional for the past 21 years.

I think most people would agree that if you purchase all-cash or only hold one mortgage at a time and pay it off before moving on to another mortgage, your overall returns will be reduced because of a slower velocity of money.  

Austin has 118 people moving here every day, has the state government and huge university to bolster its economy along with being a huge tech hub and now soon a medical hub. 

They're often slower markets meaning vacancy can be a little higher as well.  

Risk tolerance will decrease over time, so the returns as a percentage will on average slow relative to the early years as I gradually deleverage over time and am slower to releverage.

I have a short term rental on the north shore and it does very well in the summer but slower in the winter.

I think most landlords starting out have a far greater chance of loosing their property in a bankruptcy proceeding,due perhaps from a long term illness or some other medical bill.

If I'm understanding this correctly, that is around a $1,600/mo payment for the entire duplex (Estimated total PITI), and in this slower market could rent for $1200/side.

Are you selling or leasing to medical staff, retail managers, tradesmen, etc?

And if you pay yourself a management fee, you should be able to setup Solo 401K plan (best for further RE investments) and MERP (medical reimbursement plan - thus shifting medical expenses from personal to business side).