Levi goes out pretty frequently because he sits by the back door and looks at me.
I take him out when he wakes me up (usually between 7 and 8), and then right before I leave for work at 9. I can usually come home on my lunch break (1-2) and he goes out again then. And then I take him out at 5 when I get home, around 8pm, and then right before bed around 11. So...that is usually around six times, which might be overkill, but he LOVES to be outside.
The fewest times I'd take him out would be 4: when he wakes up, when I get home from work, evening around 8pm, and before bed.
They aren't always extended walks, sometimes I will take him out just to relieve himself and then we go right back him. But he loves to run and play, so he's never ready to go back inside.