Look at it another way, if you had a small number of paid off properties, you could replenish enough CASH every couple years to buy properties outright and avoid mortgages all together. 

I do know that cost is what makes up everything, the biggest items being earthquake and then anything related to community security like a guard (we don't have) or cameras and server etc. and in some cases where the HOA needs to replenish reserves based on some updated reserve study.

My two cents would be that, unless you see a quicker path towards being able to replenish your capital after spending it...a highly marketable degree like MIS could give you a great source of capital to invest later however you see fit.

The water management for Phoenix and its surrounding communities rely on underground aqueducts which are replenished in the same way that the reservoir behind the Hoover dam is replenished.  

Thats why many top flight PM's require 1k to 3k in reserves to stay in THIER trust account and be replenished if used.  

And since you'll have 20 income streams you can replenish it faster than with a single property.  

Whenever you use anything out of the budget you suspend taking cash out and replenish the budget.

Since then, I've recieved a new job and am making significantly more money, so replenishing an adequate reserve is my top priority right now to avoid this mistake in the future.

MOst of them need HML to replenish their cash.. so they can't wait 6 months for a title co to write title insurance. 

And than, if doing it smart, we get a line of credit, say $500k, that we can just grab as cash whenever, to secure more properties as all-cash offers, and once closed our lending partner will just finance us out and replenish that line of credit.