If you hire a company to do the job make sure they have their own liability insurance for the type of work they do.

Will depend on several factors like the type of property, type of tenants, your risk tolerance, other assets you own, your estate planning, laws where the property is located, etc.Any lawsuits would be limited to the assets of the LLC and not your personal assets (assuming you run the LLC appropriately and the corporate veil is not pierced).

Most of the time mold will not be this type of strain but it depends on geography and length of time left to fester.

What type of houses/buildings are you focusing on?

As I look through listings of commercial offices for sale, I see some of them listed as "Sale Type: Owner User" and some are listed as "Sale Type: Investment". 

@Billy Britton I am sure there is an opportunity for someone who wants to take on the challenge of dealing with this type of tenant.

Hello, Was looking for feedback regarding  what type or when a master key setup makes sense to add to our portfolio of properties. 

There's a max of 4 units on this type of situation for primary residence though.

The course combined with my BP lurking has got me feeling quite confident with the real estate lingo, different types of loans, and the basic concepts. 

That being said, they are all going to be very specific to the type of property being purchased, financing used, rented, flipped, commercial, residential, etc.