Change Mac Software Update Rate Using Terminal Command
By default, your Mac checks for software updates once a week. If you want this check to run more often (or less often), you can change how often your Mac checks for updates with a simple command in Terminal.
Open Terminal (Applications> Utilities) and enter the following command, replacing 1 at the end of the number of days you want to pass between checks (for a check once a week it would be seven, once a month, it would be 30, etc.):
by default write com.apple.SoftwareUpdate ScheduleFrequency -int 1
That’s it, hit “Return” and you’ve changed the refresh rate to whatever you want.
How to Change the Frequency of Your Mac Checking for Software Updates | iDownloadBlog