Like any business you need enough cash, and cash flow to stay in business. You need to plan your revenue streams so that you can pay your bills, buy supplies, pay staff etc.. Can you charge enough to do this?? Charge too much and no one will sign up, charge too little and you go belly up.
- various sized gis
- protective gear
- elect + other utilities
- legal wavers
- Attorney fees to CYA
There is probably alot of other stuff but this should give you something to think about. Sometimes hobbies transfer into business, sometimes they don't. There is a huge difference between being a great practitioner and dealing with the business side of things.
Good luck and let us know how it turns out.