OS X Mountain Lion has a handy automatic update system, but unlike previous versions of the operating system, you can’t set the frequency of updates. If you want to update more (or less), OS X Daily shares a simple Terminal command to allow you to control the process.
With all types of vulnerabilities getting patched by Apple all the time, the default behaviour of searching for updates once a week might not be enough for you. To change it, launch Terminal (Applications > Utilities) and enter this command:
sudo defaults write /Library/Preferences/com.apple.SoftwareUpdate ScheduleFrequency 3
The above example changes the software update check to once every three days. You can change that to any number you like for more (or less) frequent checks.