In addition, managing OOS properties (when you move) is more challenging (especially when things go wrong - For us it was getting hit by 2 hurricanes about a year apart in Gulf Shores Alabama) and will likely necessitate the use of professional PM.I believe if you continued to hold the properties you will do fine over a long hold period. 

The landlord is complying with a government agency’s order to vacate, order to abate, or any other order that necessitates the vacating of the dwelling unit as a result of a violation of Saint Paul city codes or any other provision of law

Hail damage on roofs is common every few years, necessitating roof replacement.

Be sure to check your local laws regarding what you can ask about the animal, condition the person has which necessitates the animal, and what tasks the animal performs.

Causes corrosion necessitating a condenser replacement.

The exception to having to be able to cover both property's expenses would be if you can document the rental income of your first property - which would necessitate you moving out of it first and having it rented.  

I haven't had the best luck with it, but probably didn't give it the attention it necessitated. 

But, if ever questioned, you just need to be able to explain/document the “unexpected” situation that necessitated the move.  

It also has a floor issue that necessitates it being replaced.

The words "at my discretion" necessitate the contingency.