Desktop
On desktop, Slack marks you away after about ten minutes without activity in the client.
Mobile
On a phone, closing or leaving the app sets you to away without waiting for a timer. Notifications can still reach you, but your status changes.
More than one device
A person can have several Slack clients connected at the same time, and Slack decides your status from them. In practice, being active on the device in your hand and idle on the one on your desk can give results that surprise you.
What this means for your schedule
- On days you only use your phone, your status will show away whenever the app is closed.
- If you want your status to follow your hours whatever device you use, schedule it from the cloud.