Taking over a self storage business

[Mike A.]

We're moving into Self Storage.  We just took over a around 300 unit self storage unit outside of New Haven, CT.  Keeping the same team, but installing a general manager to oversee the operation.  Brings in around 30k a month, but the one problem I have is that about half of that is in cash. I do not like handling cash, and the banks do not like cash either. However, I am concerned that if I push the clients who are paying in cash to credit, they will leave. There are two other self storage businesses within two miles of ours; and one of them is already modernized. 

Any tips on the best way to manage this business? I am also looking for ideas and suggestions on the best ways to modernize it as well. It was an old 1900's warehouse that was converted back in the 90s into a self storage building.