unexpectedly, my ex-STR that did not get an STR permit when quotas were enacted, I got notice is getting its STR permit.  

However, the value of your labor generally cannot be included in the cost basis for depreciation purposes.Accelerated Depreciation: A cost segregation study would identify components of your property that can be depreciated over shorter periods, such as personal property and land improvements.

It's available for certain components of any kind of properties.

If income grows faster than rent then the home appreciation can still accelarate rapidly especially when city inventory is reducing....Also the very basic component of home appreciation is money being circulated and not primarily the income in that area.

It applies to certain components only, such as carpets, appliance, fences etc.4.

In that case, it may make more sense to convert existing components of a home (attached/detached garage) into additional rentable space rather than building an additional structure.

Insuring old housing stock can certainly have an added insurance component. 

If, while running your numbers, the returns are within range to your criteria, do not lower the expenses to "make it work", but just know that some months may be higher, some may be lower, and if you have the cash reserves to support a higher bill or unexpected repair, then the underwriting at least helps you mentally prepare ahead of time.Any calculator, based on the inputs from any noobie or seasoned professional, will NEVER be the same as your actual numbers.

As for the cheaper markets, I would look to do mid term rentals in the Rust Belt near hospitals like the Cleveland clinic to maximize the income to help mitigate the downsides and unexpected expenses associated with those markets.

We don't use them as collateral, but we like knowing that if something unexpected comes up, our borrower can handle it.