While it's nice that Windows 7 is so vigilant in keeping the computing world healthy with updates, power users prefer to handle it on their own. According to Microsoft's statistics, nearly 90 percent of Windows 7 users allow updates to install and restart the system automatically. 2.38 percent want to be notified before install; 3.44 percent want to be notified before download; and 4.88 percent have update checking disabled.
The problem with the autoupdate and restart model is that some users end up losing unsaved data, which is quite user-unfriendly. Microsoft is going to change this in Windows 8 with a 72-hour grace period for automatic updates and restarts.
Microsoft plans to dramatically cut down on the number of mandatory restarts by consolidating all of the restart-required updates into a once a month on Microsoft's "patch Tuesday" (the second Tuesday of each month). For critical security updates, however, Microsoft will still roll those out immediately.
When it comes time to restart, Microsoft will give a 72-hour grace period for the user to save his or her work and restart to install updates. This reminder will also display itself on the login screen. At the end of the 72-hours, Windows Update will go ahead with the restart—except in the case where the system detects that you have some "critical applications" still open. In that case, Windows 8 will then immediately remind the user upon the next login that he or she must save work and then restart within a 15 minute window.
That's putting a lot of faith in Windows to determine whether or not your system is ready to restart. All changes in update frequency and behavior considered, though, it's definitely a more user-friendly approach than Windows 7.