The following briefly describes how WinSparkle-enabled apps behave from the user's point of view:

When the application is launched for the first time, WinSparkle does nothing yet, so that it doesn't distort user's first impression of the app. It's only when the user uses this app for the second time that they are asked if they want to check for updated versions:

If the user agrees, then WinSparkle will look for updates periodically on app startup. No UI is shown during the check, everything happens silently in the background. When a newer version appears in the appcast, WinSparkle pops up a window with information about the update, including HTML release notes (if they are provided):

As you can see, users have the option to skip this update if it's not worth downloading for them or if they're too busy at the moment. Remind me later simply postpones this notification until the next time the app is used.

Install update downloads the new version's installer and launches it.