The neighbor has an identical configuration and installed drains so the water would go into the main drain of the house.

They are supposed to last for 3-4 years in smoke detectors and have a shelf life of up to ten years, which is meaningful since these detectors do not drain the battery until water completes the circuit. 

Uneven like cracked and rising/sinking, or uneven like sloping toward a floor drain?

When you drop a tool (camera, auger, etc) down one of them, it gets pushed by the U in the direction of the other cleanout. 

The place where we are putting the new right drain tub is very uneven. 

There's an "order" for rehabbing a bathroom, if you've never done it - trash the vanity & toilet, plug the toilet drain, I hire a tile-removal guy next, then hack out the tub- bring in my plumber to stub out for the vanity, install a new tub valve & move the drain ( I've never had one line up right).

Between money out the window and down the drain if you dont plan to bifurcate the utilities on old buildings like Joel says dont even buy em if your profits are eaten up by the utility companies.

In 1946, knob-and-tube was still possible, but not as common.fuse panel versus breaker panel;electrical system of insufficient capacity for modern, electronic living;Plumbing:galvanized supply and/or drain lines.  

Our portfolio also was based on BRRR and we were self managing and thoroughly enjoyed once we finished the property only to have our new tenants put baby potatoes down the drain or block the toilet or break the washing machine only to spend a Saturday or Sunday trying to get someone to fix it.

Little did I know, but her son developed a weakness for meth and drained my account to feed his habit.