I get the following numbers.INCOMETotal Rent: $31,200EXPENSESVacancy: $2,564Taxes: $4,200Insurance: $120Repairs & Maintenance: $2,290Property Management: $2,290Leasing Fees: $1,300FINAL NUMBERSTotal Expenses: $10,201Net Operating Income (NOI): $18,434Cap Rate:3.07%I might be a bit off on some of the assumptions/expenses, but this is a high level estimate on what I expect income and expenses to be.

Assumption will likely have a low audience as it would have to be owner occupied, and most investment minded owner occupied want low down.

So then you're under the assumption that it's doesn't have lead paint.And if I remember right, the EPA has a guide on it's website, regarding lead certified contractors, and the rules around disturbance of know lead paint.

I was making one assumption too many.  

Etc.My assumption of what the cost to rehab this building I think is more than I wrote into my original numbers.

Notably physician loans can be up to much higher amounts than my current income since the programs run under the assumption of a dramatically increased income post-residency.

Many believe unrealistic assumptions and often apply those assumptions to the wrong property classes.In our OPINION (always verify yourself!)

The last thing they want is to buy an asset based on the assumption that they will get market rents, only to have the city come in and re-control the rents at the old below-market prices, because the de-control was done improperly the first time around

However, I love to continue to challenge that assumption and am always open to new viewpoints! 

As has been posted elsewhere - you need to be really careful when using any of the "Rules of Thumb" espoused in REI - 50% Rule, 1% Rule, 2% Rule etc.Use these Rules of Thumb as screening tools to know if a deal is worth looking at a little more closely.Once you get into the level of due diligence that the OP is asking about, you're breaking down the underwriting into each specific line item, based on historical operations of that actual property, or on your assumptions about the current "market" rent, expenses, vacancy etc.