But it is very easy to "fall into" a rental property out of necessity or convenience when one moves or upgrades their house. 

If we continue to have the inflation we are having and reduce the benefits / monetary supply we will see more defaults (which I think will end up as BK's) as the majority of americans do live paycheck to paycheck and as food and necessities continue to increase significantly, people will not be able to afford their homes.

I have always been a proponent of free market solutions to real world problems and there is no emotion involved in the calculation of economic equilibrium.John’s situation is a reminder that the hardworking people who service America will increasingly struggle to afford life’s basic necessity of shelter, and this reality has second and third order economic effects that reach far beyond John.The affordable housing crisis is not just about struggling blue collar workers and single mothers….it threatens the stability and economic prosperity of our entire society.

As for a business license, the necessity depends on where you are, so look into your state's rules and reach out to local authorities for some clarification.

What if it costs so much to buy food and other necessities that people can't afford their rent?

While speaking Spanish doesn't hurt, it's by no means a necessity and most people who purchase in Mexico don't.

Despite the necessity of property management (and its potential pitfalls) we are looking at REI as an exit strategy from the traveling lifestyle.We are mainly looking to buy and hold small multi-family properties for monthly cash flow - question still being - if this was YOUR situation where would you move?

I have them put it in writing and require a letter from an MD that it is a medical necessity.

Keying the same is not a necessity it is a convenience.

Just a few thousand more to lose...there was nothing really BIG this year, but the necessity of not biting off more than my business model can chew is very important.