When Do Downloads Happen on Clients?

It's been a while since I added a post.  Let's start up again with a quick one.

I was recently asked when do SCCM clients download updates and when would they show the notification balloon in the system tray - here is the answer:

1.  SCCM clients download updates according to a deployment-specific setting in the Deploy Software Updates Wizard (DSUW).  They begin downloading at the time specified in the "Make Software Updates Available" setting on the Deployment Schedule page.  If you select "As soon as possible" then the updates will start being downloaded as soon as the deployment policy hits the client.

2.   The notification balloon is displayed immediately for deployments without a deadline and only after updates have completed download for deployments with a deadline.