In the markets I'm in, I run into knob and tube wiring, galvanized plumbing, asbestos flooring, and lead paint. 

I spent about 6 month on a feeding tube and vividly remember the Doctors telling my wife the odds were not good. 

Home was built in 1916, has solid bones, foundation, and a new roof, although electrical has multiple generations of knob and tube and shielded wire with some new romex.Purchase Price: 149k $37,250 (25%) Down Payment + $3,750 Net Closing Costs30 Year Fixed 3.875% LoanCurrent Rent: $1,350 per month (675 x 2)Expenses:PITI: $780CAPEX: $135Vacancy: $100Maintenance:$100Current Monthly Cashflow: $235Immediately after close rebuilt rear stairs, replaced kitchen faucet, a fridge, and a water heater (with seller cash from close).

Pex tubing is an excellent product for re-routes.

He found a crack in the fireplace that I fixed with some stuff from HD that comes in a caulk tube and is made specifically for fireplaces.

After that would be a "bump key" (you can watch a you tube video on how to do this).

I had a tube of regular construction adhesive and it kept sagging so I ran and got a tube of grabber which holds fast and strong.

In my case, the failed deals were with people on their way down the tubes, and I could have figured it out if only I had checked harder.

A lifetime of work could go down the tubes in an instant.

Reconnect the meter; open all the facets, anti-freeze drains. 3/4 copper tube is rated at 700 psig working pressure, burst at 1.5 time higher than that.