The ultimate test is what the market will bear.

getting a 96 and above on every single assignment and test was insanely hard, but I did it....This project will set my business up in ways that would take me 10-15 years....That makes this worth the risk

Professional time tested investors:10.  

Since you already have an STR license for the property, it may be worth it to at least try and test the waters with an STR bookings and see how it goes.

With systems and procedures in place that are time tested to welcome longer-term tenants and give investors a hands-free experience.The industry is maturing year over year with the backing of necessity.

There are 6 tests called the WhiteCo factors (named after a tax court case on the subject) designed to figure out the permanence of individual assets to see if they qualify for short life treatment.

Make sure you run a detailed financial analysis and always do a rental stress test to see how the numbers hold up under different scenarios.

The city has been working on implementing lead swab testing for rental properties, that is something to consider when purchasing properties built prior to 1978. 

If you didn't do soils testing when you purchased lots, now would be a good time to understand any other hidden costs.

My general method is to assume (in the beginning) a sudden and drastic depreciation in order to stress test the financials and make sure the risks are managed properly to my risk appetite, which is quite hedged.