A fantastic Wall Street Journal article reviews the renewed interest in vocational training, manufacturing and hands-on labor fields.

There was no way to know during inspections because you can't see behind walls and everything was working at the time.Versus I had another client buy a home built in the 70s.

Several had mint green walls with dark brown trim, and hardwood floors that hadn’t seen love in a very long time.

You can charge rent at fair market value and then gift the rent back under the annual gift tax limit.

+1 with @Jaron Walling on applying asap @Lisa Mallory.

If the walls were damaged enough to require patches as opposed to just filling small holes or if an entire wall or the room needed to be repainted entirely then I would charge for that.

Intuitively, probably just do a price reduction because once you open up walls, who knows what else you might find.

Inspections are good start, but they don't check anything that the inspector cannot see so once you start opening walls, you might be in a big surprised.

You'll need to figure out how to wire it (it's not that tricky, a lot of devices have a 12v power supply) or pick a different model that can plug into a wall but has similar specs. 

When you choose a living situation with other people above, below or beside you that share walls, especially an older building, you should not be surprised that you may hear babies cry, toilets flush, alarm clocks, phone calls, etc.