One source of cities to avoid is Neighborhood Scout's 100 most dangerous cities.Disaster Risk - Some parts of the country suffer frequent natural disasters.

@Janki ShahAlso, have you reviewed the pm plants get renters?

It was the size of a quarter and was from where my wife had a potted plant.

In either case, all of the rest of my tenants who pay their rent and live up to their obligations would have to suffer for the one or two that can't/won't pay or do right.

That changed after I had a tenant, after the tragic death of his live in girlfriend, suffered a bout of depression so severe that when I visited him, not only was the lawn not mowed for over six months, but looks like he didn't have a haircut, shave, or bath for that long.

Most leases will contain something like this:If Lessee fails to pay Rent, or otherwise Defaults under this Lease, Lessor may use, apply or retain all or any portion of said Security Deposit for the payment of any amount due Lessor or to reimburse or compensate Lessor for any liability, expense, loss or damage which Lessor may suffer or incur by reason thereof.I would not expect to give it back in this case, because essentially they have broken the agreement, but again it depends on the language of the lease you've had them signed whether they are "entitled" to it or not.

A short radio interview on Plant Money in Mnpls opened with a tenant receiving a $400 rent increase from $1200 to $1600.

Regarding the rent question, if the market dips a lot and demand suffer, rental income can dip too.

@Michael Plante I've considered that, but I also really like the cashflow, even if it is halved. 

Had to re-plant new trees as well as make substantial donation for each missing tree to a City sponsored tree planting program.All said and done, it was worth it to me but it is quite painful to be held responsible for stuff the previous owner did over several decades.