You would definitely not want to only update annually.
As for cPanel, why not select the tier you prefer (RELEASE is recommended) and have it set to automatically update daily? The only time that it will actually run any update is when RELEASE has a new version.
For MySQL, it will update with cPanel if you have it set to automatically update as well.
Those are set in WHM > Update Preferences area.
For Apache and PHP, I'd suggest updating monthly by running EasyApache and using the latest PHP 5.3 at that time. Right now, PHP 5.4 is still considered to be experimental, and PHP 5.2 is deprecated.