Unpredictability introduces risk.  

Also, I would NOT want a house in a flood zone because the insurance rates have unpredictable futures (from what I understand).

It is nearly impossible for a tradesman/contractor to show up at a specific time because each job he is working on will take more/less time and the travel can be unpredictable.

Maryland weather is unpredictable this time of year...it was 70 degrees on Christmas, but will be below freezing at night this week.

Jeff,Turnover time being what it is, maybe the better thing to do is to try to get the turnover staggered so as not to happen all at once.One way to achieve this is to have leases that have differing end dates, even if it means using a 9 month lease or 13 month lease.Then, only evictions and lease breaking will cause the turnover to occur in unpredictable timing.

@Giovanni Montesclaros If you are looking at Georgia properties, you need to know that the body of law and practice surrounding delinquent property tax is complex and often unpredictable in our state. 

I don't count on appreciation, its fickle and unpredictable, and you may not get any appreciation. 

So you find a big housing surplus there, which keeps prices down--and appreciation, though it does occur, is very spotty and unpredictable. 

The more eyeballs who weigh in, the more factors subject to unpredictable action, the worse it can be.

And the timeline for closing it completely unpredictable.