A large majority of the piping is located in the basement under the kitchen. 

When economy goes down the tenants tend to move to cheaper warehouse space at less rent per sq ft or back into their home office to try and save costs. 80% of small business especially office work on small profit margins so any major shift they feel it more.Apartments in certain classes people think they are darlings and can't do any wrong.

They are starting to see corrections in the major cities.

It works the majority of the time.  

You are not doing a big Rehab where you replace major components.  

Keep lent increases modest and wait for a turnover for any major rent increases.

Make sure you know what you are buying and more importantly that the wholesaler knows what they are selling, be on the lookout for major defects in a property.

Minor Updates, now major construction.

If the Govt shutdown goes on for an extended period of time & the piggy bank needs to be replenished then yes this will create a major issue for Landlords.

I am 24 years old and will finally be graduating with a double major in Finance and Entrepreneurship in May 2019.