This enabled you to convert this unit while the tenant was still in place!  

We currently use a google spreadsheet that pulls in MLS info and Zillow info automatically and it auto-populates ARV using 90% of the Zestimate (I know...yuck...but it's at least a quick and dirty number that enables us to know if we want to dig deeper).  

This thread was initiated not to agree on the best return metric but as an academic exercise to enable me to understand why the annualized return (IRR) goes down over time for a subject property I was analyzing. @ Stephen Greenway correctly explained that the decreasing irr comes from holding the property and averaging more modest and sustainable cash flow returns over the long haul bringing down the initial "flip" return. 

All on Sub2, or is your angel investor enabling you to do cash purchases?

Regardless of your ultimate ambitions, I'd encourage you to start locally and expand as your resources (time, marketing $, buyers, support team, etc.) enable.

Most of this growth is being channeled into the western urban county.There's enabling land use legislation in the works: As of today, Snohomish county is nearing the end process of lowering the lot size minimums for Duplexes to the same size as SFR, instead of 150%, so conversions should be relatively simple to permit. 

Accelerating the payment of some taxes is well worth it to enable you to get financing.Be sure to aggressively appeal your property tax assessments downward, if at all possible, and shop aggressively for the best insurance rates (and terms, such as looking for "actual cost" coverage with high deductibles), as many insurers have increased rates sharply in the last year.

This will enable you to buy more doors faster.

What strategies did you implement to enable you to retire?

If the applicants are straw applicants or non-existent then the remaining tenants might not meet the income requirement and/or you could end up with a situation where a straw applicant has enabled criminal elements to occupy the unit.Sally, Joe and Eric apply for your unit, they pass and you rent to them.Later you find out:Sally and Joe moved in with Bob.Eric isn't a real person, he is a made up person, a stole identity basically, provided to you to pass the application screening.andYou find out that Bob is setting up a meth lab in the basement of your unit.I don't think that's ok as long as the checks clear.