To be more precise, ROI, calculated as (gain from investment - cost of investment) / (cost of investment) does not go down with time, unless you generate losses over the years.

John Yes, that is precisely why I think it is overrated with respect to cashflow, it is very difficult to find a property that will leave you above water after doing the numbers.

Some tenants even sort based on sub-structure so just making sure all of the details are as precise as possible. 

., if I’m dealing with someone in, say, Chicago or Austin, I know precisely which local operators are closing quickly and which boutique lenders are staying nimble.

Also, I think this could be more precise than my list.

I'd also think it would be difficult to precisely estimate all costs that will be paid at closing (e.g. prorated taxes) so that seller literally walks away with exactly the amount you discuss with them. 

This is precisely why I specialize in a niche or two. 

There will be varying levels of precision, but it will help you understand where to focus both your time and your capital.

Where as the auctions the inventory comes to you in a nice precise manner with professional sellers who are motivated IE banks..

Just keep in mind unless you're exclusively using a single marketing method that there is absolutely no way to determine precisely that media/message's return numbers.