Excellent question Mike!

A great source for how to do that is Frank Gallinelli's book, What Every Real Estate Investor Needs to Know about Cash Flow and 36 Other Calculations.I think you don't want to treat the problem as a Mother-Of-All-Excel-Formulas.

I watched Brandon's youtube video using the 4 square method and my CoC Return was 40.4% vs using the excel spreadsheet punching in the same numbers but coming back 10% lower.

Excellent work and great return.

Excel has this build in NPV(discount_rate_per_period, periodic_cash_flows).

Here you should build an excel model, but one rule of thumb is that it should be less than 33% of your income.

@Marcia Maynard offers excellent advice... to which I would add (in light of a recent experience) that an "appropriate" shower curtain should mean a non-porous one.  

If you are able to self manage then I would use excel, but if cloud storage with minimal input from you is what you're looking for then I would pay someone to write a software based on the cloud system and you would be able to track everything.

I excel at finding those guys. 

Building a quality trustworthy team is not always simple and it takes work to maintain the team (even local takes work to maintain a quality team).As for buying your primary residence I have two considerations: 1) how long do you plan to live in the area 2) how are the long term appreciation outlook (in LA the long-term appreciation outlook historically has been excellent).