Either if you're an admin in the Team Settings page, or if you're changing your own settings, you'll be able to activate or deactivate the Do Not Disturb mode.
When it's ON, Nikabot will only check in with each user on the days when they're online at the check-in time. This mode is useful for, for example, external contractors who are online on Slack only on the days when they work for your team's projects, or for part-timers who work less than 5 days a week.
When it's OFF, Nikabot will check-in every day from Monday to Friday, even if the user logs off of Slack before checking in. When the user logs back on Slack, they'll have a message from Nikabot waiting for their reply.