**Have clear and meaningful goals with that investment (providing good stable housing, planning for retirement, creating generational wealth, safety and stability for mental health, tax strategies to keep more of what you earn, etc.)

It was a real health hazard.

=)  What IS scary and going to cost you money, and energy especially in San Francisco is Payroll Taxes, Health care regulations  and other time keeping regulations that will keep you on your toes.  

Funny story, I was majoring in public health and wanted to work for the CDC as an epidemiologist.

If some tenant decides your wifi is not secure enough, they could cause you all kinds of headahces with their complaints (and depending on their personality, their threats).

There are many other cities to invest in where there is less risk from the local economics and health of the housing market, let alone the decreased (or non-existent) fire, medical, and police response.

What if without permits, the smoke/CO detectors were not installed properly or in the proper locations, or electrical or plumbing work were shoddy causing a fire or plumbing leak and mold and tenant health issues, etc.

And I'll tread lightly around the second question, but is your father in good health?

Showing non-commercial statistics is missing IMO the biggest threat to non-commercial residential pricing.  

When it comes to the safety of my family I would be insane to ignore this very real threat, so I put in a radon mitigation system.