The most frequent problem I had was where they're dead, then you have to hope there's been a probate and you get a deed from the heirs and/or beneficiaries. 

"this property is in a not-so-great part of town", or "the neighbors have a pit bull that can be intimidating" or "there is a fire station across the street, and we frequently hear fire truck sirens at all hours"). 

For seasoned investors, it does seem like deals will be coming more frequently, especially if you have been in a continuous direct mail cycle for six months or more.

In fact, @Brandon Turner talks to guests about self-directed IRAs fairly frequently on the BP Investment Podcast so check that out too!

Committing to and frequenting a group helps keep you 'motivated' and 'updated' in your market. 

A few years ago I was calling people and running all over town to make a deal, now I get to turn down business pretty frequently.

I have a strong credit rating.I do not own a primary residence.I'm a Veteran and qualify for the VA loan.I travel overseas a lot for work (gone about 3/4 of the year), but make frequent short trips back home.I've been speaking with an agent in Central Florida for the past 2 months and have been registered within the MLS system for that area.I'm hoping to buy 4-5 rental properties by the end of 2020 in or around Tampa / Orlando.

Duplexes usually turn more frequently, cost more to turn, and sit on the market longer than "good" SFR's.

You're quote goes right in my notebook so I can see it frequently while I'm writing down notes on condo developments we're looking at in our market.  

In this market small multi families are not traded frequently meaning they do not have comps for these properties.