I calculated what my monthly living costs were and multiplied that by two.

Multiply that times four (yes Ill pay myself rent to beef up my savings).I'm in a college town near a military post and two major plants.

Anyone on here use any advanced mathematics during deal analysis like determining rent increases, such as using Lagrange multipliers on a constraint curve of a function of price and vacant to maximize profit.

This indicates that a balance has been struck between the jobs that create other jobs through a multiplier effect and jobs that do not or if they do the multiple is low and indicates a stable economy and hence a stable housing area.Doctors, Engineers, Business owners, etc. have multiples of anywhere from 5-20 on a first level tier.

.),  Sewage is usually a multiplier of the water usage.  

No, but I can do my little part to affect change & profit while doing it.I also like the idea that I can make the cash flow multiply in short order by reinvesting in additional lower cost properties.

Take your provable monthly income before taxes and multiply by 45%.  

Mathematically, it is simply the inverse of the Gross Rent Multiplier (GRM), using monthly rather than annual rents.

So  in doing due diligence I'm apply the GRM, but the subject property rents vary how would I calculate GRM effectively?

To crunch a few numbers, 6 hours/day at $20/hr multiplied by 6 days equals $720 in saved costs.