That is the hard part. I worked literally 3 years 7 days a week and often 12+ hours. Then, I got sick :( While it was rewarding in many aspects, it also was maddening. And it is a grind. Most successful people start stores and sell them or have their whole family working.
At least here, where rents are so high, it is crazy. You must have a good business plan and enough money to survive without an income for at least a year. 90% of new businesses fail. That is a lot!!