Actually the use of percentages on the expenses related to income rental properties are usually very accurate measurements based on hundreds of thousands of rental property statistics.

But if you disregard all that time+money invested, then yes, being a doctor will statistically give you the highest pay on average. 

If you are assuming a certain return on equity that is above the ~5% or whatever in the mortgage, it makes some sense, but that seems like a fairly bold assumption.I guess... if the house appraises at X after a rehab, and you take out X, how are you going to have a positive, or even close to zero, cashflow at that point?

Check the specific homes' tax payment, the neighborhood, other public records.Now, I spend time to run statistics of the MLS data to see what is a price range I can consider.

Would update or paint the front door with a bold color along with adding landscaping and mulch.

Does that statistic hold true for your rentals? 

Yes, there is a risk that their value quickly falls in a market crash, but I feel that statistics are on my side, and that I can make up for that risk by having a large amount of money in relatively liquid index funds.

Not sure what the statistics are on abandoned buildings, but there's way too many.

I look at cash flow over the life of the investment (not just day 1, but over the life including average historical rate of rent increases) and appreciation over the life of the investment (not just next year or the year after, but over multi-decades, based on job and population growth, housing supply & demand statistics, and long term historical averages of price appreciation).

$300,000.oo Purchased & RehabARV $500,000.oo70% rule applied, Thank you B.P. for the info, giving me the ability to present factual statistics #KNOWLEDGE_APPLIED