They require regular maintenance and sealing plus they can be sensitive to moisture and heat.

There is a garden unit below that is a little more buggy, but I think that most garden units are due to moisture. 

First make sure a lender won't freak out and that water bills are OK with no obvious sign of moisture invasion.Then I'd guess I'd tell him, any inspector will see this and I'd like to buy but want credit for a re-plumb.

Our dryer vent was venting directly into the siding that the HOA had installed on the side of our building years ago causing moisture to build under the house and the dryer air was all trapped and had nowhere to go so it got clogged really bad and broke my year old dryer.

I will look into the basement efflorenscence because it could be someting as simple as re routing the gutters down spout or maybe to much moisture outside the walls.

The toilet above was clogged and apparently the water caused a leak into the unit below.The tenants called the city, who is requiring me to Check moisture levels.

public sewer, no roof leakage, no water moisture on floor and ceiling, no mold, no structural damage, no current fire damage, no termines, no electrical problem, no plumbing problem, no lead based paint, no water wells, not located in flood area, no drainage problem, no coding violation, not a historical building, no fee associate with building, no boundary agreement, no dispute, no boundary changes, no share drive way, no party wall.  

@Jay Hinrichs Congrats jay, you give a lot to this forum and do it with a gentle touch.

We've been gentle with his rent over the years, and it's a relationship that's worked pretty well for all of us.Anyway, the oldest spreadsheet I could find was from 2015. 

I'm admittedly being impatient in wanting to buy soon and my realtor is *gently* suggesting that in this seller's market with limited multi-unit inventory (and esp. in my city where we're expecting an appreciation boom), my cash flow calculation should be income vs. mortgage/taxes/insurance/property manager only (without factoring in the "savings expenses" i.e., repair/vacancy/CapEx).