Critical Updates keeps you informed of when a background update of the listed components occurs. These are controlled by the command-line softwareupdate tool and by App Store preference settings in System Preferences.
Critical Updates refreshes the Components table on launch, and about once every 60 minutes, if left running; it polls the App Store for security updates on launch, and about once every 10 seconds while running. Critical Updates has a very low energy and resource footprint, and can be left running with virtually no impact on system resources.
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