If one unit is infested, and you only treat that one unit, the pests could just move to another connected unit. 

There goes 2 years of cash flow.Or worse, your roof starts leaking and the other owners don't want to deal with a special assessment so they vote for a cheap repair job which doesn't quite solve the problem.You put a tenant in and find your neighbor, an owner, likes to play the drums at 2 AM or maybe is a hoarder and has a roach infestation. 

Just a little bit of the backstory… I work for a pest control company in Jacksonville Florida and we were called in to take care of a rodent infestation at a customers house whom his father had just passed away.

We caught a young infestation before much damage was done and now were protected by a renewable bond.

Evidence of current or past rat infestation in attic.  

Evidence of current or past rat infestation in attic.

I've moved on to MUCH greener pastures.From my experience, most investors - even my target of the "fix & flip" crowd will run you ragged, going from one mold-infested wreck to another. 

Bed bug infested (I mean in every vent/trim piece) and he smoked meth so it was all in the walls.

Given no signs of bugs being present right now, I'm optimistic the problem will be solved soon.A couple notes on bed bugs:- they enter your house randomly- they are not tied to the "cleanliness" of the property- they are an absolute pain if you have an infestation- I would highly recommend paying for zippered mattress covers if you have a furnished house hack like I do- spray seems to workI was staring down a potential HUGE headache and $3,600 expense, but it appears that we may be fine with just spray method. 

My tenants moved out of one of my rentals leaving a mess and a German Cockroach infestation.