When does your portfolio turn to a business

[Michael Ellis]

This may be a loaded question but how or when does your real estate portfolio turn into a “Business”? Meaning at what point do you hire employees, quit other income streams etc… Is the money coming through cash flow from rental properties or buying and selling… 

I am 21 and just starting out and this of course is the plan for the next 5-10 years but I want to plan ahead. 

Thanks