Vrex
The Vrex application checks for and installs new updates every time it is launched.
Oculus
The oculus software is will check for updates when launched and will prompt you to install when the download of the update is complete and ready to install.
SteamVR
SteamVR is updated by logging in to the Steam application. Steam automatically makes sure that SteamVR is up to date
Vive Console
The Vive Console prompts for available updates on startup.