Also make sure you have exit strategies in place in case STR's are all of sudden banned or permitting is restricted down the road.  

I understand that as an individual, to some banks I am restricted to have either 4 or 10 conventional mortgages under my name.

I see condos for rent by the week all the time, yet when researching properties to buy, rental restrictions are usually 3 mos. 

Employment, income level restrictions if allowed, credit score all worth listing to eliminate losers and save you some time and effort.

As a buyer you need to understand what an arms length transaction is,that you will typically have a 30 day deed restriction and at times a 120 day deed restriction if selling for more than 120% of purchase price. 

Zoning restrictions? 

No area may be more restrictive than set forth by the CA ADU rules. 

State or local laws may be more or less restrictive.  

It didn't occur to me that my lender would have restrictions. 

I'm starting out with Rental Properties and, just my luck, California is trying to pass a Bill that will, from my understanding, put restrictions on how much a landlord can charge for Rent for their rental units because of the current ridiculous cost of living here.