Hey Cory,
You are analyzing deals and making offers, so you are getting more knowledgable all the time. Keep plugging away.
I am a novice, but the numbers that I use in my calculations (or educated guesses) are:
8% vacancy
5% cap ex
1% (of the property value annually) maintenance
I know you and I have talked off line and we are in very similar situations (stationed overseas with ties to the the Dayton area and trying to break into the investing back there). From all I have heard these last few month it seems like the Dayton market is pretty saturated with investors (both in and out of state) right now. This, coupled with low housing inventory, seems to be driving up the prices on properties.
I would say one big paradigm shift that happened for me recently is that I have focused a bit less on trying to find a great cash flowing property. I don't want to buy something that looses money, but, I really like what I have seen in the development and progression of area, especially the stretch between Dayton and Cincinnati, which has come a long way even since I graduated med school back in 2010. That is why I have started to care less about the cash flow numbers and instead look at whatever positive cash flow I come up with in my calculations as "buffer" while my hope is to rely more on mortgage pay down and hopefully (and I know some people will cringe - sorry) rent appreciation over time.
That change in thinking makes a lot of the properties quite a bit more attractive, although it is admittedly a less conservative approach.
Just keep on looking, you never know when the a good opportunity is going to appear in front of you so you always have be looking ahead and be ready to move when you see an opening.