Before I give my answer I'm making the following assumptions- Your credit is decent, you have stabe income and make decent money; your debt to income ratio is relatively low. 

The average U.S. government debt has a 7 year period.  

Debt financing will be slim pickings

Think about it, if you are buying something at a 5% cap rate, but interest rates are 6%, the debt payment exceeds the income.

@Chris Kay beleive you can do DSR loans without a job as they qualify the property, not the borrower.You'd still need 20-25% down though.That's where you have a decision:- Pay down the mortgage, setting yourself up for a future refinance to free up your VA Entitlement.OR- Save up for your next acquisition.Only YOU can make that decision as you have to be comfortable with the increasing debt-load risk and the additional time to manage everything.

The main drivers1) Local Inventory2) 10 year treasury(macro)3) Personal Debt levels(macro)4) Real Unemployment(not the unemployment number but real white collar job loss ratio'd to part time jobs). 5) Industry proliferation(can't tell me a tech or finance hub moves like a health hub).To tell me #2 will derive from the same inputs as it did in Sep/Oct, I'm willing to bet it won't.

Taking the higher of the two, that's 52k in debt service for 12 months.

I think what you describe is pretty much standard performance for rental properties if your not paying cash and I am just assuming your putting max debt on them to try to get your return numbers into your criteria..

I always make sure that the properties are cash flow positive, but the large bulk of the money I make from them is from the other items (appreciation, debt paydown, tax benefits, etc). 

Probably not, but I felt better having that debt paid off.