Curb offers, bad tenants, how to avoid unknown horrors....

[Brian Garlington]

What steps do you take to minimize the possibility of inheriting potentially bad tenants in an occupied rental? 

Let's set aside the obvious answer of, "Don't buy the rental if you can't see the inside and/or talk to the tenants first." because on curb offers you aren't allowed inside until you have an accepted offer.  

Some obvious ones are probably, 

1. Lawn and/or driveway looks unkept

2. The inside of the cars in the driveway look dirty and unkept

3. Front porch has lots of "junk" outside

Any input on what some of the not so obvious things may be?