Downloading, saving and installing Windows Update manually may be done if you need to save the updates for some reason or if you find that you are unable to update you Windows using Windows Update.
Updating windows manually
But if you -- like most people -- are using Windows 10 Home, you'll need to use workarounds to stave off Windows 10's aggressive automatic updates.
The most obvious -- albeit laborious -- solution is to install updates at times when it's convenient for you.
If you're like me and you've been perpetually putting off backing up your machine, you don't have any restore points to fall back on.
So you're probably going to be stuck doing a System Repair.
Update, May 15: With the Windows 10 Creators Update, Microsoft has largely addressed the forced updates that often resulted in lost work.