But, my fiancée went and looked at the property, she met up with the landlords PM who spilled the beans on the place. apparently there where dead decaying rats in the walls, and one of the units had flooded every year consistently, there was more...I just don't remember it all.  

I would tile the walls, just don't forget the waterproofing. 

@Rush Wall, thank you!

Are there tons of holes in the walls?

If you are like me, I never know which wall color or carpet color to choose.

Are you going to have high-end finishings like granite countertops, marble tile, hardwood floors throughout, vaulted ceilings, 9' walls, etc.  

Have you opened up walls? 

By and large, most people were not superstitious, and didn't have an issue with the idea of what was beyond the wall.  

And, you got into part of the work, pulled a wall down and discover that the addition a previous owner did was wired improperly and has to be completely rewired.  

Even if you have to jack up walls and replace every stud from the inside, it shouldn't be half that.