Experience on a variety of equipment, makes etc. is essential along with financial needs - to support your business needs to take care of potential customer. Start by developing a list(s) of what you need to develop a customer base, how you can get source of parts for various brands and a line of credit, equipment beyond a tool box to service equipment, plus chain hoist, access to technical and parts manuals and other service literature pressure washing, exposure to service training classes or just on the job training, building, towing/hauling, liability insurance, etc & put a $ sign next to everything. F Fro the near future keep your day job.
You need to honestly access how much time you have spent on servicing equipment at a customers location doing service work beyond routine maintenance - like oil, filter changes , lube, etc. This is not a complete list and others may add other consideration.
Starting out on your own can be a good thing - if you plan well. and willing to work beyond the 40 hours work week - - remember you can't do it all all by yourself.