If you sell you will need to pay some form of tax and that will greatly reduce your purchasing power. 

Does it have electrical, good roof, good foundation, slab, good framing, is there any plumbing, are you on sewer or septic? 

But it needs a fair amount of work (not necessarily now) but likely over time.) the biggest ticket items are likely to be electrical and eventually the boilers.

Many are not even aware of the power of bonus depreciation, much less know those benefits will begin to diminish starting in 2023. 

Some basics: 2x Units - located on the 2nd & 3rd Fl, ea is 950 sqft, they are 3bed 1bath, off street parking, electric utilities not included, includes washer/dryer/dishwasher/stove in unit.

Here are a few points of information:Construction prices are high in area ($300+/sf)Site can accommodate slab on grade and utilities (water/sewer/electric) are at streetTargeting 3br/2.5 bath (maybe 1 car garage).

First step for me was electrical because I had old fuse boxes with some knob and tube wiring, which needed to be updated so I could add overhead lighting, dishwashers, GFCI/regular outlets, exhaust fans, ceiling fans, etc.

However, I have been using the BP BRRRR calculator tool for some offers I have made, and my question for the experienced BRRRR investors is this:If you rehab the property to the point where almost everything is new (roof, kitchen, baths, HVAC, electric, etc), why do you still need to factor in 50% of the rent as going towards expenses if you don't expect any?

@Hunter HeimerI would recommend HVAC, plumbing or electrical.

There aren't sewer lines at the property, just electric and cable lines.