You’d be surprised at how often I hear a customer complain about being bugged by Software Updates. I’ve even had one customer who refused to run them because of the inconvenience. Running software updates can often be vital to having a smoothly running machine and we always recommend running them.
The chances of having problems from a software update are typically very remote and shouldn’t keep you from running them. If you’re really concerned about something like that just wait a few days and read the tech blogs to see if anyone is reporting a problem with the update.
Now that the standard admonishment to run your updates is out of the way, I can tell you how to temporarily get Software Update to stop bugging you. These tips are specifically for 10.8; some of the tips definitely will not work in other OS’s, and others haven’t been tested for an older revision.
Option number one is to just disable Notification Center for the day. There are two ways to do this: the first is to option-click the Notification Center icon and it will turn grey. You can also swipe downwards from within Notification Center to show the on/off toggle. This will disable Notification Center for the day and you won’t get any reminders including Software Update.
Option two — when you get the pop up notification in the upper right corner of your screen, just swipe to the right on the banner and it will be ignored for the next few hours.
Option three is a semi-permanent method that is done from the update tab in the Mac App Store. Just right click on the update you want to ignore and choose Hide Update. This is only semi-permanent however. You can get the update back by pulling down the Store menu and choosing the Show All Software Update option to see all your hidden options.
Your final option (which should work for all revisions) is to just go into System Preferences, choose Software Update and then uncheck the box for Automatically Check for Updates.
I don’t recommend options three or four, but if you’re dead set against running updates then these two are your best options.