There is a business side and there is the residential side- 4 Apartment units.

I am in the business.

I am in the business.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

The schools ignore personal finance and business and hence people enter the world totally clueless as to basic concepts of business and finance.  25 years ago when I was financing small investors I made a loan to the purchaser of a small 12 unit apt complex.  

personal would be fine, but I would get a business credit card.

But that seems like a lot of busy work.

But 1500 per month isn't that expensive if it helps you motivate, analyze, close and properly operate a self storage business it was just an investment in your growth towards your goals.

Additionally, it aids in evaluating the feasibility of projects, allowing you to focus on the most profitable opportunities.

My gut tells me I need my own liability protection--I'm in business with Airbnb but don't exactly fully trust them--but like I said, it's difficult and expensive to obtain.