But if you ask me what is the most important to have when acquiring multiple rental properties with multiple tenants, I would say that the number one priority is having a very strong insurance policy structure as your first line of defense for any unexpected/extraordinary events.

Share value added content in posts and they get voted up (unless the OP does not like the answer and then ego and human nature kicks in and they get defensive).The cowardly internet dumpster replies get voted up as well.

That is, playing defense when it comes to money might not sound all that sexy, but I bet there are 10,000-20,000 investors who would have given their kidney to not have lost their shirts in 2008. 

Insurance plays an important role as the first line of defense against nuisance lawsuits and common events like slip-and-falls.

"Take what the defense gives you."

I use home warranties as my first line of defense.  

The current tenant is a small-time defense contractor. 

There’s a saying in Alaska about which hand gun is best for personal defense against Grizzlies.

Kind of like if you were a quarterback and you had to audible in the middle of a snap count, in order to read the defense and call the play to match what they were giving you. 

Their fragile health condition is not a defense to your liability.