I recommend you have some amount of coverage for catastrophic events and injuries.

Each time, society convinces itself that the current boom, unlike the many booms that preceded catastrophic collapses in the past, is built on sound fundamentals, structural reforms, technological innovation, and good policy"

Admittedly this is a low-probability risk yet catastrophic if it occurs, & it occasionally does.

And in a catastrophic downturn you can lose a property or two and not hurt your retirement life style. 

If the tenants must move out of the property for a set time frame or possibly have to break the lease completely because the damage is catastrophic then loss of rents will kick in. 

In a catastrophic event, could you lower the rent and stay solvent?  

It is a bit mind blowing that we can now access such a vast resevoir of wisdom here, kinda makes up for all the time wasted on nonproductive internet crap:)The warchest therory has another downside; similiar to folks endorsing gold to hedge against catastrophe, what happens when the storm passes and you and everyone else now has to turn their gold into cash at the same time?

Anything over 6 months is catastrophic and you will probably just let the property go into foreclosure.

It will also be much more diversified because you can split your 30 K investment into many investments, so one particular bomb is not going to be catastrophic.

The consequences of not having proper reserves can be catastrophic for the owners at the time the repairs are needed.