The main point I was making, and suggesting, is all REI need to be highly proficient in math as well as in Excel. 

Proficiency doesn't come over night.

(very skilled or proficient at something.

That STARTS with becoming proficient in real estate law, title, documentation, valuation, financing, etc. 

And that's just the cosmetic stuff.Then you have the mechanicals -- electrical, plumbing and HVAC -- which can each add $2-5/sf, even if in a house that's in otherwise good cosmetic condition.Personally, I don't like per-square-foot estimates until you become very proficient at rehabbing...when you're new, they're more likely to get you in trouble than to help you.

I suggest my clients own 3 to 5 properties per market, then buy more in the next solid market.3) Your investment capital goes further allowing you to control more properties with higher total returns.4) Unless you're highly proficient doing all the functions of a professional property manager, you should never manage your own properties.

I'm new to all this so truly understanding my city is something I'm less than proficient at.

I have Microsoft Access and Excel and am proficient in both. 

Because the closer is not as proficient in determining sesoning time, as would it be an underwriter, double closes have gone through succesfully.

CL is constantly fighting back against the spam that clogs their servers, so to be proficient you constantly have to adjust what you are doing.