When the sales market is strong, more people purchase so there is a decreased demand for rentals.In general, rent will not dramatically decrease like we experienced with property values in the 2008 crash.

And as luck would have it the SF Bay area has seen some pretty dramatic appreciation over the decades coming out of the 70s prior to that prices were no different than almost any other part of the country and maybe lower than many.. 

So yes unemployment effects rentals, but not as dramatically as other sectors of the economy or classes of real estate.

For vacancies you could offer a discount on the 2015 rents in exchange for an bump in 2016 rents - you don't want a dramatic shock - but $300 less in 2015 for $600 more in 2016 might be appealing.    

Sometimes someone who is just so benign, so calm or even boring with perfect score and references - can be a man/woman really into dramatic lover relationships. 

We all knew laws governing the landlord tenant relationship when we bought RE so saying the the investor is being "forced into providing goods and services for free, whilst paying an attorney to break the business relationship" is a tad over dramatic.

Ok, let's dig in...There are a few different moving parts to your question that I'd like to call out before digging into the bones:A duplex is still a residential property under IBC (International Building Code) so you may wish to change this to a 3-Family for dramatic affect in your example where under IBC, a 3FH is considered Commercial, not Residential.

@Ting Lai Your tenant sounds a little dramatic if they’re talking about “pain” from no hot water and contacting a lawyer.That being said, a week is too long for your tenant to be without hot water, in my opinion.

Dropping a wall, opening up a floor plan or moving a bathroom door out of a kitchen often are easy fixes that can dramatically change a space.

As we approach the 5+ year mark I expect this number will increase dramatically.