Other than a bad flea infestation in the garage (kept an "American Terrier" locked up all day in a cage at least one size too small) and feces in a toilet the place was as she lived in it. ...We called the contractor & exterminator and they were able to completed the rehab in 9 days (new floors (including tile), new paint, new doors & misc. odds and ends)!

One run down mold infested building (sold for $80k my wife refused to allow me to bid) was pulling $1500/mo in rents from small 1bed apts., & the lower was getting $1500/mo commercial.

Animal waste are the chief contributor to infestations and progenitors of disease.

I have found lawn service, property management, pest control, etc aren't needed at my houses.

And if they just had a month-to-month agreement, they'd just give you 30 days notice, instead of having you send plumbers and pest control, etc., etc., etc.

I found out the hard way on two multifamilies in Oakland that I did offers on recently and they both had too many pest/termite problems.  

I previously had a tenant with dogs that left the rental with an infestation of fleas.

Also their choice method of cooking is rather oily so be stay on top of it with regular pest control and add in some extra bucks for cleanup when they leave.

Also, I don't know enough about real estate investment to invest that money wisely or with confidence yet, and would need to stick the proceeds into an index fund until I felt educated enough to wade into the shark infested waters.

If I just told Feh she was making up stories, she could refuse to pay rent and make me start eviction proceedings, all the while claiming that her place was infested- it is a bit challenging to prove the absence of the little mites!