That depends on the business, but mainly depends on you and your drive.
If it’s a business that’s software related or similar, then it’s much easier to grow then let’s say…a construction business, or something that requires your physical presence at a location.
Work 8-4 (or 9-5 or 7-3), then deal with obligations and your business simultaneously or one after the other, and it becomes trickier.
As others have said, if you have no family / kids / partner then you can devote many more hours to it.
Add a partner, and subtract some time from that.
Add a kid, and each kid needs time from their parent as well (unless you’re an absent parent).
There’s only 24h in a day, and it’s difficult to fit everything in, so something needs to take precedence over the others.
First thing’s first…you need to decide how badly you want it. Then figure out the path.
Where’s my popcorn…