I am a current investor in short-term rentals (STR's) in Arizona, with (4) properties that have performed very well. 

Is that liability worth the extra money it would take to have the same work performed by a licensed tradesman?

"Separate books and records are maintained to reflect income and expenses for each rental real estate enterprise.""250 or more hours of rental services are performed annually with respect to the rental enterprise.

Stick with me here, in 2008 the housing market is defective and filled with under performing mortgage backed securities.

If you own rentals in Las Vegas/Henderson Nevada, it looks like the area is going to really feel the financial effects of this.It looks like Caesars Palace and the Sahara are laying off workers, and the Wynn is shutting down 100% for 2 weeks.A lot of other busineses are going to have issue too.Here is a list: https://www.reviewjournal.com/business/conventions/whats-canceled-or-closed-due-to-coronavirus-updated-for-shows-schools-business-sports-1972937/Link to front page: https://www.reviewjournal.com/

Perk test was performed back in 1985 and it was confirmed not to perk in a certain area, but owners aren't sure which.

You're the guy that confirms due diligence has happened, or better put, you need to perform your due diligence.

Fortunately, both of these things happened and my properties are performing well.  

I worked in several different states over the last 15+ years, and I moved to San Antonio a couple years ago in large part because I believe it will perform well in the next downturn.

Note I did not mention cash flow but in practice we look at the cash flow but lower than the other criteria.We perform the value add and refi.