(We turned the attached 2-car garage into a 4th bedroom, adding equity and cash flow.)

I recently purchased a duplex and the garage is being rented out by another party.

An existing kitchen layout might work well for adding a dishwsher or microwave hood for example allowing it to be made functionally modern without a major rehab.

But the city has risks too: historic tanneries, dry cleaners, gas stations, garages, workshops, any kind of industrial use - always be suspicious of what people did with chemicals back in the 50s and 60s when the general population had no awareness of the damage

Windows get delivered just sitting in an open garage..

For example, in the modern banking system, US Treasury's are actually treated as money, they perform monetary functions.Crypto currency could be treated in the same way. 

House has 4 car detached garage, had same tenants for 4 years now.

From personal experience, outdoor entertainment areas, modern kitchens, and even beach gear can make a huge difference.

If that proves not to be the case I will auction the drive and garage to the highest bidder with the losing tenant getting to park in the street.   

There is a newly built Class A 47 unit rental property  Sky View at Crawford ( lease up from 0% to hopefully 100% and value add by garage parking, valet trash etc ) by ​Skyview Capital, a DFW based Commercial Real Estate Development and Acquisition company as General Partners.