Much to everyone's surprise, Microsoft has released what is effectively Service Pack 2 for Windows 7! Called the Windows 7 SP1 convenience rollup, this release makes clean installs of Windows 7 much faster as it includes all of the security and non-security related fixes that were issues since the rollout of Windows 7 SP1 five years ago.
We’re happy to announce today that we’re making available a new convenience rollup for Windows 7 SP1 that will help. This convenience rollup package, available to download from http://catalog.update.microsoft.com/v7/site/Search.aspx?q=3125574, contains all the security and non-security fixes released since the release of Windows 7 SP1 that are suitable for general distribution, up through April 2016. Install this one update, and then you only need new updates released after April 2016.
And since this update can be injected into Windows 7 SP1 media, it’s fully supported to mount a Windows 7 SP1 image (WIM file), then inject this update into it. See https://technet.microsoft.com/en-us/library/dd744559(v=ws.10).aspx for the details of how to do this.
This convenience update is completely optional; it doesn’t have to be installed and won’t even be offered via Windows Update – you can choose whether or not you want to use it.