Install Recommended Software Updates
By default, your Mac running OS X Mountain Lion checks with the mothership (Apple) once a week to see if there’s any new or updated software for your Mac. If there is, your Mac informs you that a new Software Update is available and asks whether you’d like to install it. In almost all cases, you do.
Apple issues Software Updates to fix newly discovered security concerns, to fix serious bugs in OS X, or to fix bugs in or add functionality to Apple applications.
You can perform this check manually by clicking the Software Update icon in the System Preferences window, and then clicking the Check Now button. You also use the Software Update System Preferences pane to change the frequency of these checks, disable automatic checking completely, and/or instruct your Mac to automatically download any updates it finds.
Every so often, one of these Software Updates has an unintended side effect; while fixing one problem, it introduces a different problem. Apple is generally pretty careful, and this doesn’t happen very often, but if you want to be safe, don’t install a Software Update until you’ve visited MacFixIt, Macworld, or MacInTouch and looked at their reports on the update you have in mind.
If there are widespread issues with a particular Software Update, these sites will have the most comprehensive coverage (and possible workarounds).
Apps need updates too. So make a habit of launching the Mac App Store application now and then, clicking the Updates tab, and then updating any apps that require it.
Many third-party programs, including Microsoft Office and Adobe Creative Suite, use their own update-checking mechanism. Check and make sure you’ve got yours enabled. Many third-party apps offer a Check for Updates option in the Help (or other) menu or as a preference in their Preferences window.
One last thing: If you see a little number on the App Store’s icon in the Dock, you have that many updates waiting. Launch the Mac App Store, and click the Updates tab.