Mike Cumbie - Precisely. 

Easy to say, impossible to do accurately, precisely, and reliably, but it is what makes all of us money.

Whether I truly understand the exp "model" or not, this statement is precisely the reason I despise MLM companies.

Modeling tax items is very difficult to do precisely.

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.

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..