And then there has to be sustainable reason why you eventually settle on a specific strategy/target.

Look at is probability of sustaining a loss that exceeds the levels of coverage.  

With that being said, I think there is plenty of work here to atleast sustain a strong rental market long term.

This has proven ineffective as most of these properties' income can barely sustain themselves [even with a "larger" (20%-30%) amount of equity down] and the ones that do have worse returns and higher risk than if you were to put money into a CD, for example. 

I know many unable to sustain heat with heat pump only in the north.

Prices went up so high so fast, I don't think "sustainability" is in the vocabulary for King, Snohomish & Pierce counties. 

For example, if the average occupancy of 1970s built properties in the sub market is 90%, you shouldn’t expect your 1970s built property to sustain 95% unless rents are below market—no matter how good of an operator the syndicator claims to be.

It surely cannot sustain this upwards momentum forever without a pause. 

I doubt that some of the rent increases noted in this thread would be sustainable in my area, but it does make me realize that as a buy and hold investor I should also be considering the future calculations as well, such as IRR. 

The long term plan over the next 5 years is to get occupancy near or at 100% and sustain for as long as possible and to also begin expanding on the additional acres.