4 days after we followed them, at roughly 80-100 a day once your account is warmed up.
The gap gives people time to see your profile and follow back before we move on, and spacing the unfollows out keeps things looking natural.
We only ever unfollow accounts we followed for you. Anyone you followed yourself is never touched.
Prefer it handled differently? We can unfollow only the people who didn’t follow back, or hold your following count at a number you choose. Just say the word.