What is often overlooked, unknown by new folks and overlooked even by seasoned dealers, are other laws related to business operations. 

With no experience in government, Ben Carson is a bit of an unknown.

I think there are too many unknowns to be getting into a gambling situation with interest rates 5 years from now. 

As a result we increased our remodel budget and timeline to account for possible unknowns.

(Maybe some AirBNB type options too.)My biggest unknown is financing.

Known needed exterior repairs are approx. 5K, inside unknown as there were no viewings.

Or, they stay in contact for years and years asking 1000's of questions asking for a video walkthrough after walkthrough with no offer ever made and the end result is still unknown. 

How should I prepare for an unpredictable, theoretical event of unknown proportion and timing, with little to no supporting evidence?

Lastly, if you're in a condo, there are a lot of unknown as far as neighbors in very  close proximity ,and you don't know their screening.. granted this isn't specific to condos, but it's just the proximity of neighbors and such... we have a rule about avoiding apartment complexes for this reason!     

If not, you have to ask yourself if it is worth the price you paid with that unknown factored in.