The storage business is pretty easy once you have the infrastructure set up. CC on file for your decent customers, remember a lot of people that need storage spaces are "in transit" either between homes, working out of the area , getting divorced and an lot dont have CC's that can be counted on to clear every month. Thats the crappy side. And people hoard crap, I have a retired friend that gets the job of clearing units for a Milton storage company, 90% of what he clears out is crap.
I'm amazed at the number of people running businesses out of a storage unit. WAY cheaper than a monthly commercial unit if a single car garage is enough space.