I once wrote here in a comment the update SP1 for Win7 would cost something, what is of course nor right. (It referred to the Office version 2010). However I think it could be useful to do this update for Win7 now. The service pack available for two years is now delivered to all users (home & business version). Microsoft will discontinue the support for Windows 7 with its SP1 in April.
Therefore Microsoft is now starting to deliver automatically the service pack 1 (SP1) for its Windows 7 operating system. They are writing a blog entry that it is a comprehensive update to reach customers who do not have it installed yet. If anyone has automatic updates enabled, Windows 7 SP1 is being installed without user intervention; so check your settings. This requires sufficient space and (if it is a laptop), a constant power supply.
The update is relevant because on 9 April Microsoft will discontinue support for Windows 7 without SP1. For the long term Mickysoft continues till 13 January 2015, to guarantee in any case its support and updates for Windows 7 with the latest service pack available, which will be then SP2.
I never let the system decide what it wants to do. I always decide. Once a mainframe system programmer always a mainframe systems programmer 
It doesn't take that much time and it can happen whilst I'm on another machine so I now do it systematically
But not for all updates surely?
Personally I now like to take an image of my system disk before any upgrade to Windows. This is because of one occasion where the update went wrong and I had to reinstall from scratch. Turning off Automatic Updates but letting them download means I get a reminder to create the image.
"If anyone has automatic updates enabled,"
I can't for the life of me think why someone would NOT have automatic updating turned on. Even the illegally activated versions of Windows Vista and Seven accept updates without a problem.
Check your settings folks and make sure automatic updates are turned on and working.
Note also that the install of SP1 takes much, much longer than the normal monthly fix package.