You should download and install all Windows Updates that are available in Windows Updates for all of your computers. If you haven’t already configured your computer to download and install all Windows Updates that are available in Windows Updates, here are directions directly from Microsoft on how to do this: https://support.microsoft.com/kb/306525
These directions are very detailed, and are easy to follow, and cover Windows XP, Windows Vista and Windows 7. Most all Windows Updates available today are security updates, and it is very important to download and install all the security updates that become available through Windows Updates. You can configure Windows Updates to notify you when important updates are available to download, or available to install, after they have automatically been downloaded, or to automatically have them installed for you.
I prefer to have the Windows Updates downloaded first, but then to notify me when those Windows Updates are available to install on all of my computers, that way I know what Windows Updates are going to be installed, so that if something with the Windows Update ever goes wrong, I can uninstall that Windows Update to get my system running correctly again.
If you configure Windows Updates to notify you when an important Windows Update becomes available to download, or when an important Windows Update has been downloaded, and is ready to install, an icon will appear in the task tray, next to the clock, notifying you that important Windows Updates are available to download and install, or install. You can then review the Windows Updates that are available to download and install, or install, before installing them.
When I work on client’s computers, if time is available, I always download and install all Windows Updates that are available, so that I know that any security vulnerabilities that Microsoft is aware of that may exist on that computer are patched, and all drivers and all Microsoft software is up to date. If my clients would download and install all Windows Updates themselves, before I work on their computer, it would save me a lot of time, and therefore save them money, because I would be working on their computer for less time, which translates to money that I would be charging them to bring their computer up to date with Windows Updates.