There are a lot of factors out there but savings is a lifestyle and some people are just incapable making sound financial decisions. 

Amenities, stay fees, wow factor, location, and unit price are only part of the equation.

Assuming that doesn't include any mortgage pay down, you need to factor in capital gains taxes. 

The ideal asset allocation for someone in your financial position depends on various factors, including your age, risk tolerance, retirement goals, and current lifestyle.

You didn't cause the problem which is a major factor in the premium impact.

the Pm isnt' even managing the repair-owner comms - it takes me forever to get responses-rent collection - happens through a portal, they aren't going and picking up checks...-3- day notice - they didn't service it for 50 days....

Timely payments are one of the largest factors in a credit score and if he hasn't had late payments since then, his score would continuously improve.

The most major factor in most markets is affordability.

You have to also factor in your vacancies and turn around costs to re-rent.  

is there a particular formula that takes all manner of factors, (employment growth, corporation development news, barrier to entry, rental rates, wage growth, etc) into account and spits out an "invest in city X" answer?