The city defines an ADU as follows:17.04.030 Definitions.

I have some strong opinions about this.I think there are five different people in every market that defines the supply/demand.1: Savvy Investor,2: Non-Savvy Investor, 3: Savvy homeowner, 4: Non-Savvy homeowner with money, 5: Non-Savvy homeowner without money.As interest rates rise, savvy investors recalculate there expected return and redefine the purchase price as needing to be lower.  

High rents alone isn't what defines a good area to buy rentals in, just like low rents won't define an area as a bad one. 

In order to make an informed decision, you need to define the highest and best use of the property and compare its entitled (paper lot) value to its “as is” value.I can provide more information on the process.

@James Austin The city of Austin defines a STR as a property rented for less than 30 days.

Some says no need for paid by paypal, venmo, credit card; some says "private owner" doesn't need (but never define what qualifies "private owner"), some says needed for all situations. 

The scope of work is well defined and the qualified people are easier to identify.

Eligible Bidders, as defined in the California Civil Code §2924m(a)(3) have the right to bid on the subject real property after the scheduled foreclosure sale. 

My husband and I are at the trailhead and just getting started, so we're working on defining our goals now.

@Lauren Kennedy, as others noted, I would first define a goal.