You should focus on more important things like understanding federal/state/local law, how to properly screen applicants, how to handle unpaid rent or an eviction, how to deal with lease violations, what to do when the neighbor's tree falls on your tenant's car, etc.

You can't evict people half the year/winter or really screen tenants.

I'm attributing this issue to being new to the game, and not executing my application/screening process as thoroughly as I should have.

Be sure to screen tenants thoroughly, especially since they will be on your property. 

I'm pretty sure that on Day 1 at Facebook, for instance, no dude sitting in front of a screen working on a team of guys that are delegated the task of improving one possibly better way to share cat pics thinks of himself as a "feline image viral distribution facilitator."

In one state, I have an agent who can place & screen tenants with my approval for a fee, then I manage it from that point on.

You may be cash flow positive with 2/3 occupied units but every scenario is different- Run the numbers with the current rents you are getting- You may have to re screen the tenants you are inheriting- Look if they are a taw or on a lease Know your state laws! 

@Thomas Hickey  Because I'm getting paid automatically and I don't have to show the property, screen tenants, etc.

If I scale further up, then it might require an actual Property Manager, because I can't be there to screen that many tenants.  

That may be too extreme for 13 months, but it could have been longer.I'm curious, in lieu of this incident, what do you intend to change (or do differently) in your current screening process so that you may avoid similar tenants in the future?