As the app developer, you will receive an email after 5 days of no traffic on your app.
If you would like to keep your app awake, you have one of two choices:
Visit the app (create traffic).
Push a commit to the app (this can be empty!).
If left alone the app will go to sleep at the 7 day mark (2 days after you receive the email). When someone visits the app after this, they will see the sleeping page:
    
To wake the app up, press the "Yes, get this app back up!" button. This can be done by anyone who wants to view the app, not just the app developer!
You can also wake apps through your Streamlit Cloud dashboard. You will know which apps are sleeping because a moon icon will appear next to the app settings. To wake an app from the dashboard, click the moon.
