Does it produce cash flow?  

My wife and I have been doing this for 8 years and have never paid more than $800/month for our mortgage as a result. 

Adjust over time as you see statistical results (that you should be tracking).Have you hooked up with any cash buyers yet?

This implies you need to find good investment properties that produce better initial cash flow than the average purchase. 

I've been reminding him for years, with no results, and had pretty much given up, but still try every once in a while.  

Failure to do so may result in a loss of coverage.

Thank you for your response @Sam Smith , so I’m still trying to learn what makes a deal a good deal, I don’t want to blindly invest money into something that will produce a negative cash flow.

Likely any market in the U.S. with good schools is not going to have much opportunity for great ROI at the moment due to an influx of homebuyers and the resulting inflation in home values.

I suppose that's what I mean when I say I want access to the capital now, because I can invest in a way that produces now with cash flow and appreciation and even more later by using leverage, 1031 exchanges, depreciation, etc. 

Both of these will produce some results for you.