How much time are you prepared to spend away from them at critical moments of their lives? 

Low initial investment with low returns, but covers cash flow.Zoning is critical, paving needs high rents, you may as well include covered parking at that point.

Location, condition of critical systems, optional upgrades could all be categories with different rates.

@Steve Franco, you make a few critical errors in your calculations. 

But, many elements may be required to meet LL/Tenant laws, or were deemed "emergency" items that needed repair to prevent further damage, or were clear safety/health issues, where time is critical.

Like @Michael Blank said, capital is typically critical,  so its very interesting to hear how he got started and looking forward to hearing from others.  

That's not a criticism. 

It is critical to have a rock solid SOW or your project is doomed.

I have a 12 unit WW II era motor-court "motel" that I operate as apartments.I agree that it is critical to understand the municipality and retain a local architect type who knows the municipality personnel and the requirements.In my case, a change in zoning was out of the question as municipalities tend not to want to set precedent in changing zoning.

“It is not the critic who counts: not the man who points out how the strong man stumbles or where the doer of deeds could have done better.